Articles

Colonoscopy and Other Colorectal Cancer Screening Options: An Update

When I wrote about colonoscopy in 2010, colonoscopy was thought to be the best screening test for colorectal cancer because it could visualize the entire colon and could remove adenomas that were precursors of cancer. But only fecal occult blood testing (FOBT) and sigmoidoscopy had been proven to decrease colorectal cancer incidence and mortality (by 16% and 28%, respectively). Observational evidence suggested that colonoscopy would reduce the incidence and the number of deaths from colorectal cancer, but there were no randomized controlled trials, and the reduction in incidence of cancer after colonoscopy screening seemed to be restricted to left-sided colon cancers, which didn’t make sense.

We still don’t have any randomized controlled trials of colonoscopy, but a 2013 case-control study from Germany compared patients with and without colorectal cancer and found that those who reported having had a colonoscopy were less likely to develop colon cancer for up to 10 years after the procedure. And now two studies published in the New England Journal of Medicine in September 2013 have shed more light on the subject.

Sigmoidoscopy or colonoscopy vs. no screening

A large cohort study by Nishihara et al. looked at data from the Nurses’ Health Study and the Health Professionals Follow-up Study with a total of 88,902 subjects followed for 22 years. During that time, 1,815 colorectal cancers developed, and 474 subjects died from colorectal cancer. Those who had sigmoidoscopy or colonoscopy were much less likely to develop colon cancer than those who did not.

COLORECTAL CANCER Hazard ratio compared to no endoscopy
After polypectomy .57
After negative sigmoidoscopy .60
After negative colonoscopy .44
In right colon after negative colonoscopy .73
DEATH FROM COLORECTAL CANCER
After sigmoidoscopy .59
After colonoscopy .32
From right colon cancer after colonoscopy .47
From right colon cancer after sigmoidoscopy No reduction

This is very encouraging. Colonoscopy cuts the incidence of colon cancer and of death from colon cancer by more than half. And it’s clearly superior to sigmoidoscopy in detecting cancers in the right side of the colon (proximal colon).

Usual care vs. fecal occult blood testing

The second study, by Shaukat et al. was a randomized controlled trial comparing usual care to annual or biennial screening with fecal occult blood testing (FOBT). It followed 33,020 subjects age 50-80 for 30 years. Annual screening reduced colorectal cancer mortality to a relative risk of .68; biennial screening to a relative risk of .78. All-cause mortality was not reduced. There was no benefit of screening below the age of 60 in women, although there was for men.

10% of participants had a positive FOBT at each screening, and 83% of those were further evaluated by colonoscopy, with polypectomy if polyps were detected. Long-term reduction of risk of death from colon cancer was consistent with the effect of removing adenomas that would have progressed to cancer and death.

It would not be appropriate to draw conclusions about the relative efficacy of FOBT vs. colonoscopy from these very different trials. There is still no evidence from randomized controlled trials directly comparing FOBT with colonoscopy, but such trials are in progress.

The recently introduced fecal immunochemical test (FIT) is more sensitive than the traditional guaiac test for FOBT, so it is likely that the results of fecal testing will improve. What we can say is that both types of screening are effective, and that the studies support current screening recommendations of FOBT annually, sigmoidoscopy every 5 years, or colonoscopy every 10 years from age 50 to 75. Patients can choose any of these after considering cost, complications, convenience, and other factors. Two other possible options are screening with barium enemas and virtual colonoscopy. Virtual colonoscopy (with CT) requires the same bowel prep as colonoscopy and if an abnormality is found, regular colonoscopy is still required for follow-up. Barium enemas miss about 50% of the cancers that can be found with colonoscopy. Both of those involve considerable exposure to radiation.

My colonoscopy experience (anecdote alert!)

I thought I would share my own colonoscopy experience for interested readers who want to hear a personal story about what it involves and what it’s like. If you’re not interested, just skip to the next heading. After reviewing the evidence and the pros and cons of each option, and considering my personal feelings about colonoscopy, I elected annual FOBT screening, and this year one of the three FOBT tests was positive for occult blood, so I had to bite the bullet and have a colonoscopy. It didn’t cost me anything, since as a military retiree I’m covered under Tri-Care for Life, but it was time-consuming. It involved 3 separate appointments on different dates: (1) with my primary provider to get a referral to the GI clinic; (2) in the GI clinic for pre-procedure history and physical and for education for informed consent (both by a physician assistant), and for instructions about the prep (by a nurse); and (3) for the procedure itself, which also required a time commitment from my husband who was required to be in the waiting room throughout the procedure and drive me home afterwards, since I couldn’t drive after IV sedation.

The thing I dreaded most was the bowel prep, and most people agree that’s the worst part of the procedure. I got a new and improved split-prep regimen. For 3 days before the colonoscopy I had to avoid high-fiber foods like popcorn, beans, seeds, multigrain bread, nuts, salad/vegetables, and fruit, which made meal planning a bit problematic. The day before colonoscopy, I was only allowed clear liquids, and was told to drink 8 ounces every hour, to include water, apple or white grape juice, broth, coffee or tea (without milk or cream), clear carbonated beverages, Kool-Aid (not red or blue), Jell-O (not red or blue), popsicles (not red or blue). They gave me a huge plastic jug with bowel prep powder with instructions to fill with water, mix, and keep refrigerated. Late in the afternoon on the day before colonoscopy, I had to start drinking an 8 oz glass of the bowel prep every 15-20 minutes until the level was down to a mark they had made on the jug. I was also instructed to continue hourly clear liquids up until midnight to prevent dehydration. On the morning of the colonoscopy I was instructed to skip my usual medications and drink the remaining solution, 8 oz. every 15-20 minutes, finishing 3 hours before leaving for my appointment. The solution didn’t taste very good, and it was difficult to force so much down in such a short time and the frequent intervals required watching the clock carefully or setting an alarm. I didn’t get nauseated, but I felt bloated and uncomfortable, and of course I spent quite a lot of time on the john including throughout the night (didn’t get much sleep). No cramps, just a lot of liquid, and it became hard to tell when I needed to get to the bathroom. By morning only clear liquid was coming out.

The procedure itself was a breeze. I was admitted with a patient wristband, given a hospital gown and an IV was started. There was a long wait, and eventually my gurney was rolled into the procedure room, where I was asked to lie on my side and given a sedative through the IV. The next thing I knew, I was waking up in the recovery area. They told me they had removed one small polyp, and the pathology results would be available in three weeks. I had no pain afterwards, didn’t even pass a lot of gas as they had warned I might. Went home and slept for several hours. My abdomen felt vaguely uncomfortable for about 3 days afterwards.

The polyp was a 4 mm adenoma, and they recommended a repeat colonoscopy in 5 years rather than the usual 10 year screening interval. I dreaded having to go through the bowel prep again, and in 10 years I would be past the upper age limit for screening. I discussed this with a gastroenterologist I knew, and he agreed with me that in my case my personal risk factors for colon cancer were so low that it would be reasonable to wait longer than 5 years, so with any luck I will never have another one. I sure hope I don’t. The whole rigmarole was unpleasant and complicated. I sure hope science and technology will come up with a better screening test sometime soon. There has to be a better way!

I certainly don’t regret getting it. I considered it medically necessary because of the positive FOBT, and I no longer have to wonder whether all is well in my colon. They got a good look throughout and removed the one small benign polyp. That’s very reassuring.

Pros and cons of colonoscopy

Colonoscopy is undoubtedly the best option for examining the entire colon and removing polyps that might develop into cancer. But there are risks: perforation of the bowel (in less than 0.2% of patients), bleeding, anesthesia complications, dehydration from the laxatives, rupture of the spleen (rare), infection, nausea, vomiting, allergic reactions, and even death (in 0.003-0.03% of patients). There is a substantial time commitment and an average cost of over $1,185 in the US. The total cost to insurance companies and the government must be staggering. There is inconvenience, time lost from work, and an arduous bowel prep. There are not enough colonoscopists to screen the entire population as recommended. A gastroenterologist can spend a huge chunk of his time doing these routine screening procedures. According to a British report, clinicians did up to 448 a year, with an average of 205. I’d think a gastroenterology subspecialist would get bored and feel frustrated that after his 14 to 15 years of education after high school, he was spending so much time on such a routine procedure. As the population ages and the demand for colonoscopies increases, I wonder whether it wouldn’t make more sense to train PAs (physician assistants) to do the job. It’s basically a matter of manual skills, coordination, and practice, and I think PA’s could be taught to do it as competently and safely as MDs, and doctors could be on standby to assist in managing any complications that developed. It would save money and leave the gastroenterologists free to exercise the clinical expertise that they have trained so long to attain.

Conclusion

New evidence supports the current recommendations for colorectal cancer screening. Screening by either FOBT, sigmoidoscopy, or colonoscopy significantly reduces the incidence of colorectal cancer and the death rate from colorectal cancer. We still don’t have evidence to directly compare the effectiveness of the different options or to show a decrease in all-cause mortality. Trials are in progress that should provide that evidence. Meanwhile, if you are approaching the age of 50, you have a decision to make: not whether to be screened, but which screening test to choose.

Posted in: Cancer

Leave a Comment (59) ↓

59 thoughts on “Colonoscopy and Other Colorectal Cancer Screening Options: An Update

  1. Dan says:

    I will adopt colonoscopic screening to hedge my bets but will do everything possible to prevent colorectal cancer in the first place (meaning eating a whole foods, plant-based diet, exercising vigorously every day, and taking a low dose aspirin from the age of 45 as per Rothwell et al). If meditation helps, hell, throw that in too. You could then call it [much reviled] “holistic preventive health care”.

    1. stanmrak says:

      Aspirin is a drug, certainly not without risks, and no disease has been shown to be caused by a lack of aspirin in the body. There’s plenty of science-based evidence that suggests that taking aspirin daily may not be such a good idea, especially if you are healthy to begin with.

      http://www.webmd.com/heart-disease/news/20120607/daily-aspirin-worth-risk
      http://www.medicalnewstoday.com/articles/243265.php
      http://www.mayoclinic.com/health/daily-aspirin-therapy/HB00073

      1. Harriet Hall says:

        Yes, we’re well aware that there are risks from daily aspirin, but there are also studies showing clear benefits for people at risk of heart attacks and strokes. As with any other treatment, the risk/benefit ratio for the individual must be considered.

        The USPSTF recommends the use of aspirin for men ages 45 to 79 years when the potential benefit of a reduction in myocardial infarction outweighs the potential harm of an increase in gastrointestinal hemorrhage.
        Grade: A recommendation.
        The USPSTF recommends the use of aspirin for women ages 55 to 79 years when the potential benefit of a reduction in ischemic stroke outweighs the potential harm of an increase in gastrointestinal hemorrhage.
        Grade: A recommendation.
        The USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of the use of aspirin for cardiovascular disease prevention in men and women age 80 years or older.
        Grade: I statement.
        The USPSTF recommends against the use of aspirin for stroke prevention in women younger than age 55 years and for myocardial infarction prevention in men younger than age 45 years.
        Grade: D recommendation.

        The argument that no disease is caused by lack of aspirin in the body is ridiculous: pneumonia isn’t caused by lack of antibiotics, either.

      2. WilliamLawrenceUtridge says:

        Since aspirin isn’t a vitamin, why would someone suggest it is used to correct a deficiency*? Aspirin is used to control symptoms (notably pain) and perhaps it’s the fact that I have a nervous system, but I think controlling pain is a valid use of it. Aspirin also has various useful effects on the body such as reducing clotting, though the specific risk to benefit ratio is obviously complicated and must be taken on an individual basis with decisions informed by things like family history and other risk factors.

        Aspirin’s biochemical effects on the body are similar to other plants known to have other effects on the body in that they are complex and multi-faceted. People take it for the same reason they chew on other roots, berries and leaves, in the hopes that it will somehow stave off some infectious agent or the ravages of aging. If the compound has an effect, doubtless it will have adverse effects as well (such as St. John’s Wort affecting photosensitivity and interfering with medication, or ginkgo seeds causing seizures). But why would you ever take these anyways? It’s not like people ever suffer from St. John’s Wort or ginkgo deficiency.

        *Because they’re a dishonest douchenozzle.

      3. windriven says:

        @stan

        “no disease has been shown to be caused by a lack of aspirin in the body.”

        Your ignorance flaps and flutters like a city pigeon, landing here and there to litter the intellectual landscape with dollops of wet, foul stupid. Do you ever think before you comment?

  2. mdseuss says:

    The prep is certainly the least fun part of the colonoscopy. My prep was done primarily with Miralax and it didn’t seem as bad as my wife’s experience with other bowel cleanse preparations. Consider having the colonoscopy done without sedation! It really isn’t that uncomfortable and they can have the the sedation at the ready if you change your mind. I will most certainly go without sedation again in 5 years.

    1. windriven says:

      @mdseuss

      I didn’t know sedationless colonoscopy was an option. I’ve been avoiding a colonoscopy for years, largely because I hate the dopey feeling after sedation.

      Now I just have to decide what to do about health insurance*. ACA has made it imperative that I stop offering company health care coverage. But in WA there are three ACA health insurers, not one of which covers my personal physician or my preferred hospital – a modern medical center that is part of a smallish regional hospital group. So I will have to dive into the individual insurance market and see what is available.

      *Most of my employees are semiskilled manufacturing workers earning less than $25 per hour. ACA appears to be a good deal for them as the subsidies are generous – presuming that the actual premiums, once the pool has taken shape, don’t skyrocket. But for those of us in higher earning ranges it is troublesome, at least in the near term.

    2. Squidocto says:

      I had a sedationless colonoscopy once, and asked the doc to place the monitor where I could see it. He obliged, and also talked me through the whole thing, giving me a tour of my own colon. Fascinating!

      1. windriven says:

        Love it!

    3. Joanne Benhamu RN says:

      Sedation-less colonoscopy is an option for some but I would not recommend it for everyone. How well you tolerate a colonoscopy will depend on several factors:
      - Individual tolerance to pain
      - cultural factors (some countries perform these procedures without sedation)
      - existing (and active) bowel disease e.g.: Crohns, Ulcerative Colitis – performing a colonoscopy or a sigmoidoscopy on a person with active IBD would be cruel.
      - people with Irritable bowel syndrome (IBS) tend to find these procedures more painful
      - people who have had abdominal surgery including hysterectomy, Caesarian, hernia repairs etc. they ,au have adhesions (scarring) which tether the bowel and make the procedure much more difficult and uncomfortable.
      - People with anxiety either generally or specifically related to the procedure tend to require more sedation.

      (I was a Specialist Endoscopy Nurse for ten years so I’m speaking partly from my knowledge of the evidence and partly from professional experience and observation.)

    4. Nathania says:

      Miralax is definitely a better prep option. My gastro reluctantly agreed to it when I wasn’t tolerating the prescribed one very well. I think she was surprised when my bowels were clean but they were sparkling clean.

      It’s so much more gentle. I’m young and *hopefully* won’t need another one for another 15 years (and I’m hoping they develop some kind of better test) – but if/when I do, I’ll demand Miralax. (That sounded like an ad – sorry, old copywriting habits die hard).

  3. goodnightirene says:

    I think I’ll stick with the “old” prep regime, which didn’t seem half as bad as what you describe. I simply did a liquid diet all day and then some glop at the end that didn’t cause any of what you describe. The doc said I had the cleanest colon he’d ever seen. I eat a lot of fiber and very little meat. I followed the prep instructions to the letter (many people cheat from what I hear as they seem to feel they will absolutely DIE if they have no solid food for 24 hours). I didn’t have juice or broth (they were permitted), just water and a little jello.

    I will, however, demand sedation next time as I didn’t have it and felt that it was ten times worse than having babies with no meds at all.

    Obviously, experiences vary quite a bit!

    I find it interesting that you dreaded this so much. I have always thought it far better to have a colonoscopy than to sit and wonder if something untoward is going on in there. I found the prep a minor inconvenience, but I would not want to do it the way you did which doesn’t sound like any improvement at all, but rather far more onerous. I think I will ask a lot of questions next time.

  4. nyudds says:

    I have had all the procedures Dr. Hall mentions done multiple times because at age 55, a sigmoidoscopy revealed an adenoma. It was removed and later, others were found which were also removed. I have been clear for 7 years . The important thing is to get beyond the prep and inconvenience and be thankful that these methods, which reduce morbidity and mortality, can be done on an outpatient basis quickly and with certainty. I avoided colon cancer and I am grateful for two things: that I had well-trained MD’s and staff and that I worked the OTHER end of this magnificent tube for over 40 years!

  5. Kate says:

    My mom recently had to go through a colonoscopy and watching her suffer through the prep procedure I had the same thought you did- there has to be a better way to do this! Followed by- I sure hope someone finds that better way before I have to get one!

  6. Nashira says:

    Colonoscopy definitely isn’t fun. I got to have my first done a few weeks ago due to a moderately severe epusode of colitis, and oh my GOD the prep was terrible. Even after being on a liquid diet for several days, since even soup was incredibly painful despite 10mg oxycodone/six hrs, it took almost all four litres of the PEG/electrolyte solution for the output to be clear. I get to do it again in January, probably with general anesthesia, since my colon was so inflamed and bizarrely shaped that they couldn’t complete the first one under the sedative alone. Thanks, ulcerative colitis!

    That said, it beats the pants off colorectal cancer, and it got me on meds that are actually treating the symptoms of my UC pretty well. Even after spending the whole prep day crying in pain, I’m still okay about doing it again. I am still very jealous that Dr. Hall has maybe one more scope in her future, though! Stupid getting sick before you’re thirty. :)

    I’m going to link this to my mom. I know she’s not willing to get screened, but surely it’s not that terrible to provide a stool sample…

  7. ladygrey says:

    As a Crohnie (Crohn’s Disease), I always find the intense mental angst that people have around this procedure mildly amusing. I’m 26 and have had 6 (7?) colonscopies in my lifetime. While they are unpleasant and stressful, it’s almost a routine process for me at this point. The thought of going more than five years without one seems like a magical Utopia to me. I’d be happy for two years without a scope! Given the risks of Colon Cancer in Inflammatory Bowel Disease (UC and Crohn’s), I’ll have to keep getting screened for the rest of my life. At some point in the near future (usually 8 to 10 years of active disease), you end up with yearly colonscopies for as long as you live.

    That said, I’ve got a couple of pro tips for anyone having one done. Don’t do the massive jug of liquid approach to bowel prep. Go with Picto-Salix, which is a tang like powder that you mix into two tall glasses of water. It’s simple and effective. Just limit your food in take for three days prior to the prep date, stay hydrated on clear Gatorade, and you’ll be fine. Some GI’s dislike the Picto-Salix because they feel it can be “rougher”, but having tried all bowel prep preparations, I’d prefer to have a simple and quick over complicated but “milder”. Baby wipes can really help as well.

    Also, always go for sedation. I’ve had varying degrees of the “conscious” sedation as well as the sans sedation option. It was slightly surreal and interesting to watch the scope progression, but was mildly painful/uncomfortable to experience. It did allow me to have a real time discussion about my disease presentation with the GI while it was happening, as well as learn some interesting facts about my bowel, but I prefer the sedation approach more. It seemed that sedation resulted in a better recovery time and clearer results. I think having to interact with me directly during examination slowed the GI down as well as left him less able to biopsy/etc things.

    Comforted to see that assumptions about colonscopies as a useful screening process are bearing out, but wondering of lead time bias is a factor here? I thought there was a school of thought about early screening that it doesn’t improve overall cancer mortality but appears to reduce five year deaths because of early detection. Am I way off base with that thought?

    1. MTDoc says:

      I think the difference is you are not identifying cancer, but adenomas that have cancerous potential. At least for where the procedure is truly for screening. If you do find an establish cancer, then your point is well taken. However, the whole idea of screening is to remove polyps before they become malignant.

      1. Dan H. says:

        “However, the whole idea of screening is to remove polyps before they become malignant.”

        I do not see polyps as being a random inevitability for everyone (unless you have FAP or one of the familial cancer syndromes). I think there is much we can do to actually prevent polyps in the first place.

        1. Andrey Pavlov says:

          The problem, Dan, is that all the science and epidemiology point to that statement being incorrect. Undoubtedly a certain portion of these polyps are preventable. We’ve identifed a few things that increase your likelihood of developing them such as low fiber diets, high fat, high protein diets, and exposures to known carcinogens. The data isn’t overwhelmingly positive, but there does seem to be a signal there, which is consistent with a small-ish effect size.

          But there is absolutely nothing to indicate that all polyps/CRC’s could be prevented entirely. Unless you have some actual data to demonstrate otherwise?

          (which would be hard, because there are multiple lines of very strong converging evidence which indicate quite clearly that there is simply a baseline level of cancer incidence that can be decreased, more or less depending on the cancer, but never actually eliminated should a population live long enough)

          1. Dan says:

            Comparison of different populations – e.g. American non-Hispanic Caucasians with sub-Saharan Africans – reveals markedly different rates of colonic polyps and CRC.

            My guess is it’s largely about diet and DNA repair mechanisms.

            Mutagens are ubiquitous in our environment – from ultraviolet light to certain viruses to known synthetic carcinogens – so what really makes a difference is not so much exposure but repair. We have the inherent capacity to perform DNA repair to correct aberrant tumor-promoting mutations. Some of us do it better than others. To believe this is all under predestined genetic (inherited) control is a deterministic fallacy. Yes, some families have higher rates of CRC – families also tend to eat the same foods and inculcate the same lifestyle habits through generations. Inheritance of genetic DNA is not necessarily full-blown biologic destiny.

            I very much believe that CRC and other so-called diseases of affluence can be prevented. A fully reductionist, head-in-the-sand approach would be to say that we need to shove a tube up people’s rear ends starting at the age of 50 to look for cancerous and precancerous lesions because there’s nothing else we can do. But this is treating the symptom of disease instead of the cause (yes, I am fully aware that lassoing and resecting a given precancerous lesion — adenomatous polyp — decreases the risk of THAT particular lesion from becoming cancer, though of course it does nothing to the overall microenvironment or microbiota of the colon). In our current disease care system, we have become much better at treating disease than preventing disease or promoting health – a common complaint. We are remunerated to do procedures like sigmoidoscopies and colonoscopies. I believe these procedures are necessary largely because we do not adopt lifestyle modification at the population level from an early age, and this is largely due to a failure of our opinion leaders to formulate coherent and knowledgeable public health messaging.

            If you want to believe there is nothing you can do to prevent future CRC other than having serial colonoscopies starting at age 50 (by the way, the age 40-49 group is the fastest growing segment of the CRC population), then by all means get those colonoscopies and don’t modify your lifestyle. I, for one, will continue be proactive. And I’m quite aware of the epidemiology of CRC and what factors influence it (both adverse and protective).

            1. WilliamLawrenceUtridge says:

              Mutagens are ubiquitous in our environment – from ultraviolet light to certain viruses to known synthetic carcinogens – so what really makes a difference is not so much exposure but repair.

              Aren’t plants themselves a significant source of carcinogens themselves? By weight, they probably represent the greatest quantity of harmful chemicals consumed on a daily basis. Certainly some medicinal herbs are both nephrotoxic and carcinogenic, and there’s some populations for whom even common foods are dangerous.

              I think cancer is simply natural and inevitable given a sufficiently long lifespan. I would much rather eat ice cream and steak in reasonable quantities than lock myself into a limited and less than delicious diet for my entire life. I think there are too many confounds with the “western diet” (notably the “western exercise habits”) to pursue immortality through leaves and beans.

              But at the same time, even discussing things like this tends to polarize opinions away from both the evidence and one’s original standpoint. I think it’s an uncontroversial point we can both agree on that the obesogenic diet consumed by most in the first world and richer nations is a bad thing that should be changed.

              1. Dan says:

                Cancer is simply natural and inevitable if you live in a society where cancer is rampant and to be expected, and acquire the risk factors of those who live in that society. It is not so in a place like Okinawa, Japan, or the island of Corsica. Nor in subsaharan Africa or Kitiva near Papua New Guinea. I believe all the people who live in these locales belong to the species “Homo sapiens”.

                This is an ecological comparison so it’s fraught with bias, but it does refute the point that cancer is inevitable (I would also argue that dementia or coronary disease is not inevitable either). It is so sad that we have come to expect these conditions to occur – it’s a bit like a fish not knowing what water is like because they have never experienced anything but water, so they don’t have a contrast to compare it to.

                You make a great point that it is better to live a shorter life with steak and ice cream than a longer, poorer quality life on beans and leaves, but I would make the counterargument that how you die is just as important as how you live. Are you going to blow your brains out with a shotgun if (God forbid) you get a diagnosis of advanced cancer? No, you are going to fight like hell and there is a good chance you are going to be in significant pain and suffering at the end (just like my brother-in-law was – and yes he was pre-screened with colonoscopy, as I’ve mentioned elsewhere on this site). Even if you do survive it, the experience is not appealing on any level that I can imagine. To say that only FOBT and endoscopy prevent CRC is to bury one’s head in the sand and ignore decades of epidemiology and other scientific research. There are subtle but significant pressures to do just which we adamantly need to be aware of.

              2. Chris says:

                “Cancer is simply natural and inevitable if you live in a society where cancer is rampant and to be expected, and acquire the risk factors of those who live in that society. It is not so in a place like Okinawa, Japan, or the island of Corsica. Nor in subsaharan Africa or Kitiva near Papua New Guinea.”

                Citation needed.

                Cancer is most often caused by living past age 55. This is from the CIA World Factbook on Papua New Guinea:
                Life expectancy at birth:
                total population: 66.66 years
                country comparison to the world: 168

                Subsaharan Africa is most of Africa, but here is the data for Chad (I just clicked a country on the Africa map that was south of the Sahara):
                Life expectancy at birth:
                total population: 49.07 years
                country comparison to the world: 223

                The other two are just sections of two countries, and not included separately https://www.cia.gov/library/publications/the-world-factbook/ . It does show both France (Corsica) and Japan (Okinawa) having a life expectancy being over 80 years.

                This the same information from the USA:
                Life expectancy at birth:
                total population: 78.62 years
                country comparison to the world: 51

                It seems that the reason fewer get cancer in both Papua New Guinea and Chad is because they die from something else before getting cancer. The average age of death of Chad is less than when colon cancer screening even starts!

              3. WilliamLawrenceUtridge says:

                Do you think ancient Egypt was a society where cancer was expected and rampant? Don’t you think the fact that cancer, a disease that increases in incidence and prevalence with age, might becaused more by increased life expectancy rather than diet? Do you think that the tremendous genetic uniformity of these groups might be a bit of a confound?

                This is an ecological comparison so it’s fraught with bias, but it does refute the point that cancer is inevitable (I would also argue that dementia or coronary disease is not inevitable either).

                …except for the fact that these poeple still get cancer. It may be at lower rates, but it is still present. Cancer is inevitable on a population basis. And there are so many confounds – most notably BMI/obesity – that you don’t know what’s actually causing it. I think your certainty is out of step with the evidence as a whole.

                Are you going to blow your brains out with a shotgun if (God forbid) you get a diagnosis of advanced cancer? No, you are going to fight like hell and there is a good chance you are going to be in significant pain and suffering at the end

                I would attempt to make the case for the option of medically-assisted suicide. Failing this, I would attempt to squirrel away my morphine and go out with a massive overdose. Failing that, I would asphixiate myself using my car. And none of these points are evidence that cancer can be prevented by a low-meat, high-vegetable diet.

                To say that only FOBT and endoscopy prevent CRC is

                …an exagerration of a very complicated medical literature? And anyway, the recommendations are still and in general “eat lots of fruits and veggies”, I don’t think there is evidence to say a vegetarian diet will guarantee a cancer-free life (for instance, I doubt it’ll do a damned thing for DNA damage caused by ionizing radiation).

    2. Nashira says:

      Flushable wet wipes were a gift from heaven during my prep. I think a bidet would have been even nicer, but my standard middle class US house does not come equipped with such. I know it may seem like a small thing to some, but please believe us – they will make you much more comfortable and less chafed the next day.

      LadyGrey, thanks for the tip about the non-jug-of-awful laxative. I will have to talk with my doc about it when I see her next week… gives me something concrete I can ask about, besides a 5-ASA without delzicol/asacol’s obnoxious no-food-for-three-hours dosing regimen.

  8. mho says:

    Please, would you explain what relative risk percentages mean?

    1. David Weinberg says:

      Relative risk is the event rate in one group divided by the event rate in another group. Usually the groups are selected to differ only in their exposure to a single variable.

      In Dr Hall’s example, it is the rate of death from colon cancer in the patients who who received FOBT vs those who did not receive screening.

      Using nice round made-up numbers, if the mortality from colon cancer was 5 per thousand in the FOBT patients and 10 per thousand in the non-screened patients, the relative risk would be 0.5.

  9. Harriet Hall says:

    Explanation of relative risk, for instance “Annual screening reduced colorectal cancer mortality to a relative risk of .68″

    This means that people who were screened annually had 68% of the risk of those who were not screened. In other words, there were 68 cancer deaths in the screened group for every 100 cancer deaths in the unscreened group.

  10. I completely agree with your comment that there are not enough gastroenterologists to do screening colonoscopies, especially in underserved areas of the country. I’m a family physician who does colonoscopy in an underserved population, and we have two labs staffed by family physicians and gastroenterologists that can barely keep up with the high risk patients let alone screening patients. I belong to an organization, the American Association of Primary Care Endoscopy, where our mission is to help training of primary care physicians in GI procedures so they can go to these at-risk areas.

    One critical factor to consider is that not all colonoscopists are created equal. An important thing to ask your colonoscopist is what is their adenoma detection rate? This is a rate of adenomas detected in a screening average risk population over 50 years old. If your colonoscopist does not know their ADR, or it is low, then you probably either want to find another colonoscopist or do an FIT. Minimum is 30% for a male population and 20% for a female population. (Mine is significantly higher than this, but I don’t scope an average risk population–I am scoping mostly higher risk patients, often those who have been screened positive for FIT).

    1. goodnightirene says:

      Thank you for this information. I would never have known to ask, nor would I have known what to make of the answer!

    2. Joanne Benhamu RN says:

      Stuart, I agree with you. We have the same problem here in Australia. On the one hand we have some if the expert bodies calling for increased screening and encouraging people to ask for it, but on the other we have the reality that there are not enough facilities, gastroenterologists and endoscopy nurses to cope with the increase in demand that would result.

      I posted on this in Harriet’s original article a few years back, specifically regarding the problems with FOBT testing here due to an inadequate screening program.

  11. Dan says:

    My brother-in-law had a clean colonoscopy and died of colon cancer about 3 years later. Very sad. I don’t know the full details but he was a head physician and very well taken care of. In other words, for a bad prep they would almost certainly have repeated it. But no test is 100% accurate and anecdotes are only that (anecdotes).

    In general, I am not a big fan of cancer screening outside of certain indications (such as family history of disease), but of course I always follow the guidelines on this (interesting that they have urged repeated scale-backs for breast and prostate cancer screening, at least here in Canada). I have a sneaking suspicion a lot of colorectal ca. is related to lifestyle habits (obesity, glucose intolerance, sedentary lifestyle, overnutrition, highly processed foods and meats, red meat, barbequed meat, and all the crap the factory farm system injects meat with these days, not eating enough fruit/veg/fibre); some cultures with better diets have far lower rates of colorectal cancer (at least until their members immigrate to the West and adopt our habits). There is a serious scientific hypothesis that nocturnal light exposure may be a risk factor for CRC, breast and prostate ca. — again, we are going against the grain of our evolution with our activities, although humans are said to be an extremely adaptable species (at what cost?).

    Aspirin is one of the most effective ways to prevent colorectal cancer, but you need at least 5 years of therapy to begin to show an effect. The downside, of course, is the bleeding risk, and anyone with bleeding risk factors should very carefully consider the pros and cons of this decision and not take it lightly. The latest USPTF guidelines do not take into account cancer prevention (not just for colon ca, but for a diversity of cancer types), and thus tend to be a bit overconservative and only geared to vascular risk and bleeding.

  12. Jacob V says:

    Colorectal cancer is part of my genetic heritage which means I’m in for a colonoscopy every three years to get polyps removed. I had the joy of informing my 20 and 23 year old children that they would need to have their first colonoscopy when they turned 40…, they were thrilled. This type of information and procedures clearly saves lives and if it reduces the chances of me becoming a bag man down the road my diligence is assured. And Harriet, as for the bowel prep powder I was advised to mix it with an appropriate colored sports drink which makes a big difference in getting it all down on time and keeping your electrolytes balanced.

  13. MTDoc says:

    I’m curious as to why these recommended preventative procedures have a cutoff age of 75 or 80. At age 78 one begins to notice such things. Surely turning 80 doesn’t prevent one from getting colon cancer. I am due (overdue) for my second colonoscopy, based on the removal of an adenomatous polyp ten years ago. However, in spite of my procrastination, I doubt that waiting two more years will put me in the clear. This surely must be where generalizations defer to individual situations. I wonder who will make such decisions in the coming age of centralized health care.

    1. Harriet Hall says:

      I think the age limit is based on the likelihood that people will die of other causes before a colon cancer advances far enough to kill them. As you point out, the guidelines are generalizations, not rules to be slavishly followed, and decisions should be individualized.

  14. Jen Beck says:

    Thanks for outlining the various cancer screening options, you have a excellent medicine related site! :)

  15. Greg says:

    Thanks for the insight – especially regarding the colonoscopy procedure. I hope I never have to have it done…

    1. Egstra says:

      Gregg says, “I hope I never have to have it done…”

      In my book, that’s much like hoping you die before age 50.

      I’ve had 3, and will continue having them every 5 years until I age out. The first one was anxiety-provoking; the others no big deal.

      1. Greg says:

        I’m not a fan of invasive procedures so I plan to stick with FOBT screening with my hope being that I can avoid getting a colonoscopy. I don’t know what the stats are but I’ve read a few horror stories of colonoscopies gone wrong.

      2. mousethatroared says:

        If one was young enough, one could hope for improved technology that has the same benefit of colonoscopy without the downsides.

  16. Albert Macfarlane says:

    Dr Hall’s positive experience with colon cancer screening is commendable. The original World Health Organisation commentary on screening tests pointed out that in order to be successful, the test should be “acceptable, safe and relatively inexpensive.” Although Dr Hall points out the deficiencies of the various proposals for colon cancer screening, you must admit that none of them meet these criteria. In a Canadian government sponsored review of these tests some years ago, some members of a panel rejected colon cancer screening on the grounds that no test which could be fatal should be promoted to healthy persons.

  17. cloudskimmer says:

    There must be multiple preps for colonoscopy. Mine was just for the day before, didn’t involve a lot of liquid and quickly cleaned me out without lots of trips to the bathroom. Other than being ravenous the evening before and worrying that the vegetable broth I ate might spoil the procedure because it was slightly cloudy (it didn’t) everything worked out great. Nor did I feel groggy afterward, though I did get a ride home and relaxed (and ate!) for the rest of the day.

    Why are there different methods of cleaning out a colon? Can’t they be evaluated in a science based way to find what works best with the least discomfort? This looks like something that could be investigated for better patient convenience.

    1. Joanne Benhamu RN says:

      There is an extensive body of medical literature investigating the various bowel preparations.
      The ideal preparation is one which
      - rapidly removes all fecal material
      - does not alter the bowel mucosa
      - minimises fluid and electrolyte imbalance
      - minimises patient discomfort.
      Currently, there is no single prep which meets all these criteria. http://www.ncbi.nlm.nih.gov/pubmed/16733101

      The most common preparations are Polyethylene Glycol or Sodium Picosulphate.
      The former is a large volume (3-4 litres), iso-osmotic, causes minimal shifts in fluid and electrolytes, tastes salty and is more likely to cause feelings of bloating, nausea, cramping and abdominal discomfort. The latter tend to be smaller volume, osmotic laxatives and are more likely to cause fluid and electrolyte shifts which can result in dehydration, hyponatremia (low sodium level in the blood) and hypokalemia (low potassium).

      It is usually safe for young, healthy individuals to take the sodium picosulphate based preps. However, these are contraindicated in the elderly and in patients with heart or kidney disease.

      In addition, the sodium picosulphate preps have been shown to give a better preparation. Polyethylene glycol preps tend to leave more fluid sitting in the bowel (especially in the caecum).

      Ultimately, a good bowel prep is extremely important to the quality and safety of the procedure. A poor bowel prep can result in a messy procedure which is unpleasant for both the patient and the staff. It decreases the likelihood of obtaining a diagnosis. It increases the likelihood of missing small lesions and the proceduralist is simply unable to closely inspect the mucosa and it also increases the risks of the procedure such as the likelihood of the bowel being perforated.

      So yes, gastroenterologists and GI nurses take bowel prep very seriously and would like to see a prep which meets all the desired criteria as much as the patients would.

  18. Heisenberger says:

    Any information regarding the effectiveness of virtual colonoscopies?

    1. Harriet Hall says:

      Virtual colonoscopy is less effective at finding small polyps. You can read a comparison between virtual and optical colonoscopies here: http://www.medicinenet.com/virtual_colonoscopy/page2.htm

      1. Joanne Benhamu RN says:

        Yes, and if something is found which requires removal or biopsy then you would need a colonoscopy anyway. Plus, you still have to take bowel prep for both procedures.

  19. George Martin says:

    During the last 3 and half months, i had to undergo two bowel cleaning regimens;
    once to have a cancerous kidney removed and once for a colonoscopy, my first.
    the two regimes were different.

    The one for the kidney used magnesium citrate as the cleaning solution. It tasted better, relative to the glop Harriet had, and I had for the colonoscopy and much less
    volume (1 liter?). It was drank the afternoon of the operation. But it required two days of a liquid diet. Trips to the bathroom were about the same I think I remember.

    Don’t know which one I prefer at present.

    George

  20. Sam Ogden says:

    In regard to your comments about training PA’s to do the procedure.
    I am a Family doctor who works at a Family Medicine Residency Program. We are affiliated with a community hospital who absolutely refuses to allow family docs (or surgeons) to do colonoscopies. The gastroenterologists will not even allow the residents to watch them do the procedure. At the same time, they refuse to see medicaid and self-pay patients and bitch everytime we consult them on the inpatient service.
    I can hardly imagine that the gastroenterologists are going to declare a truce in this pathetic turf-war and allow PA’s to ever get anywhere near a scope, even though a chimpanzee could probably be trained to do the procedure.

    1. Stella B says:

      I learned to do flex sigs from the flex sig PA at the VA. At the time they were looking for another PA/NP to help him out with the high volume because his previous colleague had quit due to the carpal tunnel syndrome she got from doing the same procedure all day long.

    2. We are affiliated with a community hospital who absolutely refuses to allow family docs (or surgeons) to do colonoscopies.

      Of course they do! :) Colonoscopy is THE most profitable screening operation. Letting someone else pluck the golden goose? Never!

      1. WilliamLawrenceUtridge says:

        Any evidence for this claim, or is it just yet more made-up bullshit from someone who knows nothing about medicine?

        And have you considered the fact that perhaps these doctors are aware of the risks and nuances of their procedures and want to ensure their patients receive the best available care for this extremely uncomfortable procedure?

        Of course not.

        1. Joanne Benhamu RN says:

          It’s far more likely that it’s because performing colonoscopy safely and effectively requires both extensive training and then continuing to perform the procedure on enough patients on an annual basis to ensure that one maintains those skills. The likelihood of experiencing a complication such as a bowel perforation is much higher if the proceduralist does not perform the procedure regularly. It’s common sense really.

  21. Colonoscopy is a useful tool and I have forwarded select patients for this procedure, however Harriet’s overview glosses over the dangers, which are substantial. The study she presents has a glaring flaw and I’ll discuss it after a brief introduction.

    According to the college of physicians review, 0.5% of patients undergoing colonoscopy will experience serious and life threatening complications from the procedure. 0.5% doesnt sound like a lot, but needs to be put into prospective. The current medical fad is to recommend this procedure to everyone under the sun and his dog every 4-5 years, That adds up to over 70,000 serious injuries reported yearly from colonoscopy procedures. That’s more than yearly deaths from colon cancer! Most of the people who suffered these injuries had no genetic disposition to colon malignancies and would have been perfectly healthy without the scope.

    Furthermore, the damages from colonoscopic screening are underreported.

    A little known dirty fact is that colonoscopes are poorly disinfected from previous use and with modern scope mills cramming as many as 50 patients a day for the scoping, you are getting a serving of blood, mucus and germs from the previous 9 patients. The unfortunate patient who catches hepatitis or HIV in this manner does not get reported as “colonoscopy-acquired infection” and just slips through the statistics.

    Most damning of all is the finding that depressed lesions in the colon are the most likely to cause cancer and are not detected by colonoscopy at all, while the 90% of polyps that are detected and removed are actually benign and will never cause disease.

    One colonoscopy study found that although polyp removal slightly reduced death rate “from colon cancer”, it actually increased death rate “from all causes” by a whopping 57%.

    This is the flaw of the Nishihara study – it only reports “deaths from colorectal cancer” not mortality from all causes, which is important to get the full picture.

    Putting it all together, colonoscopy is an extremely profitable business ($2000 for an hour of work) and is relentlessly pushed by the medical establishment to be used as frequently as possible to maximize revenue. An informed and ethical physician will assess the genetic profile of the patient, age and lifestyle-related risks before recommending to insert anything in his butt.

    1. WilliamLawrenceUtridge says:

      Colonoscopy is a useful tool and I have forwarded select patients for this procedure,

      You don’t have patients, you have customers.

      According to the college of physicians review, 0.5% of patients undergoing colonoscopy will experience serious and life threatening complications from the procedure. 0.5% doesnt sound like a lot, but needs to be put into prospective. The current medical fad is to recommend this procedure to everyone under the sun and his dog every 4-5 years, That adds up to over 70,000 serious injuries reported yearly from colonoscopy procedures. That’s more than yearly deaths from colon cancer!

      The page you link to (well, the link that isn’t a cartoon) is to a set of articles. Which one substantiates the fact that the serious and life threatening complications rate is 0.5%, or 70,000 per year? What portion of that 0.5% is serious, which is life-threatening? How does that compare to the number of deaths of colon cancer prevented by the procedure, or those with Crohn’s disease, or irritable bowel, or any of the other conditions requiring colonoscopy? While it might be a higher number than the 50,000 deaths due to colon cancer, let’s not forget that the risk of developing colon cancer (5% of the population) and its rank in the listing of death-causing cancers (third) means screening is something that should be taken seriously. 0.5% (if a real figure and not just made up like so many of your truthy facts) is too high, but then again, so is 5% of the population developing colon cancer.

      One colonoscopy study found that although polyp removal slightly reduced death rate “from colon cancer”, it actually increased death rate “from all causes” by a whopping 57%

      One study from 1999 using technology from 1983 and 1989 on 400 people, with a difference of 55 versus 35 people. One study. What do the rest of the studies say, has this finding been replicated? Generally your citations show that science and medicine needs to improve (and has improved since 1989). Agreed. What do you add to this point beyond pretending medicine is worse and more imperfect than it actually is?

      Most damning of all is the finding that depressed lesions in the colon are the most likely to cause cancer and are not detected by colonoscopy at all, while the 90% of polyps that are detected and removed are actually benign and will never cause disease.

      So the remaining 10% should be ignored? We should only give colonoscopies to people who develop cancer, only remove the polyps that will become cancer? Do you understand the concept of screening? You know what? People shouldn’t waste money on the losing lottery tickets, they should just buy winners. Also, gamblers should only bet on red when it’s going to win.

      Incidentally, since depressed lesions are harder to detect with normal colonoscopies, does that mean you advocate the more grueling high-resolution endoscopy, with its attendant risks? Because you’re all about the best care for patients, right? Not at all about pushing the false dilemma of “if real medicine is flawed, that means I’m justified in selling homeopathy”, or whatever nonsense you consistently fail to defend explicitly.

      Putting it all together, colonoscopy is an extremely profitable business ($2000 for an hour of work) and is relentlessly pushed by the medical establishment to be used as frequently as possible to maximize revenue. An informed and ethical physician will assess the genetic profile of the patient, age and lifestyle-related risks before recommending to insert anything in his butt.

      So…you don’t think they do? You don’t think patient choice, history and age relate? Despite numerous discussions by Dr. Hall and the commenters who talk about the fact that scoping is based on age, stops once you pass a certain age, and is only one possible option presented along with a multitude of others?

      Douche.

  22. Joanne Benhamu RN says:

    It is simply not true that flat lesions cannot be diagnosed with colonoscopy. Yes, they are much harder to spot, but a careful and thorough proceduralist is trained to spot these lesions. In addition, new technology such as Narrow Band Imaging is allowing us to see lesions which were previously much harder to spot. http://en.wikipedia.org/wiki/Narrow_band_imaging

    1. Joanne Benhamu RN says:

      Regarding the issue of scope disinfection, this is a basic quality and safety issue. Any facility that is not carrying out manual processing of scopes, regular microbiological testing, tracking and so forth are failing in their duty of care.

      In Australia, endoscope reprocessing is often carried out by GI nurses, but these days the task is being passed over to technicians from sterilising departments. On the one hand this is helpful as RN’s are more urgently needed to provide direct patient care, assist proceduralists or even perform the procedures ourselves (as is becoming more common). Properly trained personnel, proper tracking systems and quality control should prevent the transmission of infection. It is extremely important that scopes are regularly inspected for wear and tear and tested after each use for leaks. I have a major problem with newer automatic reprocessing systems that claim to remove the need for manual cleaning of scopes. Believe me, most people involved in endoscope reprocessing would be delighted if the manual cleaning part of the process could be removed. It is responsible for a significant number of shoulder injuries & repetitive strain injuries in those performing the cleaning. However, I do not believe that the evidence exists yet that these machines do as good or better a job of removing microscopic debris from scopes. So as far as I’m concerned, we should be continuing with the status quo until there is stronger evidence.

Comments are closed.