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Archive for Diagnostic tests & procedures

Redefining cancer

Blogging is a rather immediate endeavor. Over the last nine years (nearly), I’ve lost track of how many times I saw something that I wanted to blog about but by the time I got around to it, it was no longer topical. Usually what happens is that my Dug the Dog tendencies take over, as I’m distracted by yet another squirrel, although sometimes there are just too many targets topics and too little time. Fortunately, however, sometimes the issue is resurrected, sometimes in a really dumb way, such that I have an excuse to correct my previous oversight. This is just such a time, and the manner in which the topic has been resurrected is every bit as dumb as the rant by the Food Babe that Mark Crislip so delightfully deconstructed last Friday. Unfortunately, for purposes of snark, I’m not Mark Crislip—but, then, who is?—but fortunately I am known elsewhere (and sometimes here) for being a bit “insolent.” So let’s dig in. We’ll start with the idiocy and then use that as a “teachable moment” about cancer biology. Funny how I manage to do that sort of thing so often.

Abuse of cancer science for political purposes

I realize that we at SBM are supposed to stay, for the most part, apolitical, but the idiocy that’s leading me to revisit a topic is unavoidably political because it involves using a profound misunderstanding of science for political ends. Specifically, I’m referring to the misuse of a legitimate scientific debate about cancer screening and diagnosis for purely political ends. First, however, for those not living in the US or my fellow citizens who might be blissfully unaware (in this case) of recent events, during the first half of October, our nation underwent what can only be described as a self-inflicted crisis that could have caused worldwide economic turmoil if it hadn’t been (sort of) resolved at the last minute. The reason for the crisis boiled down to the extreme resistance of some of our more radically conservative Representatives to the Patient Protection and Affordable Care Act, usually referred to as just the Affordable Care Act (ACA) or, colloquially, Obamacare. Normally when we write about Obamacare here on SBM, it’s to complain about how advocates of unscientific medicine and outright quackery have tried to piggyback their advocacy on the ACA in order to have health insurance plans sold through government exchanges cover modalities like naturopathy, chiropractic, and other so-called “complementary and alternative medicine” (CAM) or “integrative medicine.” In related posts, I’ve examined the evidence with respect to the relationship between health insurance and mortality and whether attacks on Medicaid as not improving the health of patients insured by it have any validity. (Let’s just say they are oversimplifications and distortions.)
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Posted in: Cancer, Diagnostic tests & procedures, Politics and Regulation, Science and the Media

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Baby’s DNA in Mom’s Blood: Noninvasive Prenatal Testing

Until recently, the moment of birth was a surprise. We anxiously awaited the obstetrician’s announcement: “It’s a boy!” or “It’s a girl!” Then we checked to see if any crucial parts were missing and we counted the fingers and toes. We had to wait for a baby to be born before we could know its sex and whether it was normal. Today, thanks to prenatal testing, we can know the sex of a fetus, diagnose a number of genetic abnormalities and malformations, and we can even operate on the fetus in utero to correct certain problems before birth. I had amniocentesis for my two pregnancies because of the higher risk of Down syndrome at my age (37 and 39). It was reassuring to know the baby didn’t have Down syndrome, and it was fun for my husband to point to my burgeoning belly and introduce it to people as “our daughter Kristin.”

Amniocentesis is invasive, carries risks, and can’t be done until the 15th to 20th week of pregnancy. Now there is a safe, noninvasive, accurate blood test that can be done as early as the 9th week. It analyzes cell-free fetal DNA (cfDNA) circulating in the mother’s blood. It sounds ideal, but there are some caveats. It’s not yet appropriate to recommend it to all pregnant women. An editorial in The New England Journal of Medicine expressed concern that pressures are promoting diffusion of cfDNA testing beyond the boundaries of available evidence. (more…)

Posted in: Diagnostic tests & procedures, Obstetrics & gynecology

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Does Everybody Have Chronic Lyme Disease? Does Anyone?

A deplorable article by Suzy Cohen on Huffington Post is titled “Feel Bad? It Could Be Lyme Unless Proven Otherwise.” It consists of irresponsible fear-mongering about a nonexistent disease. A science-based article would be titled “Feel Bad? It Couldn’t Be Chronic Lyme Disease Because CLD Is Nonexistent Until Proven Otherwise.”

Cohen says:

People often attribute uncomfortable symptoms to aging, stress, or the “aches and pains of daily living,” especially if blood tests and body scans are normal. What if you have Lyme and don’t know it? If you’ve ever been for a walk in the woods, laid in the grass, live in or visited a Lyme-endemic area, or have a pet cat or dog, you may have exposed yourself to Lyme disease and associated co-infections. There is even the possibility of contracting Lyme if you were born to a mother who has been exposed. Tick born infections can also be transmitted from blood transfusions.

That pretty much covers everyone. Who hasn’t been for a walk in the woods, lain down on the lawn, or had a pet? (And incidentally, are there no editors or proofreaders at HuffPo who realize that the past participle of lie is lain and that infections are tick-borne, not tick born?) (more…)

Posted in: Diagnostic tests & procedures, Science and Medicine

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“Postnatal depression blood test breakthrough” or Churnalism?

Postnatal depression blood test breakthrough” proclaimed the headline. The UK Guardian article then declared:

British doctors reveal ‘extremely important’ research that could help tens of thousands of women at risk.

Here it comes. Readers were going to be fed a press release generated by the study’s authors and forwarded undigested by the media but disguised as writings of a journalist.  If only the journo had asked someone in the know about the likelihood of a single study yielding such breakthrough blood test for risk of depression in new mothers.

The story echoed earlier churnalism from Sky News, British satellite television news service:

There is evidence that if you can identify women at risk early you could treat early or introduce measures to prevent or stop the process of the disease.

A study of 200 pregnant women, published in the Journal of Psychiatric Research, found two molecular “signatures” in the genes that increased the risk of postnatal depression by up to five times. One in seven new mothers suffer from depression.
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Posted in: Diagnostic tests & procedures, Science and Medicine

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The difference between science-based medicine and CAM

“Alternative medicine,” so-called “complementary and alternative medicine” (CAM), or, as it’s become fashionable to call it, “integrative medicine” is a set of medical practices that are far more based on belief than science. As Mark Crislip so pointedly reminded us last week, CAM is far more akin to religion than science-based medicine (SBM). However, as I’ve discussed more times than I can remember over the years, both here and at my not-so-super-secret-other blog, CAM practitioners and advocates, despite practicing what is in reality mostly pseudoscience-based medicine, crave the imprimatur that science can provide, the respect that science has. That is why, no matter how scientifically implausible the treatment, CAM practitioners try to tart it up with science. I say “tart it up” because they aren’t really providing a scientific basis for their favored quackery. In reality, what they are doing is choosing science-y words and using them as explanations without actually demonstrating that these words have anything to do with how their favored CAM works.

A more important fundamental difference between CAM and real medicine is that CAM practices are not rejected based on evidence. Basically, they never go away. Take homeopathy, for example. (Please!) It’s the ultimate chameleon. Even 160 years ago, it was obvious from a scientific point of view that homeopathy was nonsense and that diluting something doesn’t make it stronger. When it became undeniable that this was the case, through the power of actually knowing Avogadro’s number, homeopaths were undeterred. They concocted amazing explanations of how homeopathy “works” by claiming that water has “memory.” It supposedly “remembers” the substances with which it’s been in contact and transmits that “information” to the patient. No one’s ever been able to explain to me why transmitting the “information” from a supposed memory of water is better than the information from the real drug or substance itself, but that’s just my old, nasty, dogmatic, reductionist, scientific nature being old, nasty, dogmatic, reductionist, and scientific. Then, of course, there’s the term “quantum,” which has been so widely abused by Deepak Chopra, his acolytes, and the CAM community in general, while the new CAM buzzword these days to explain why quackery “works” is epigenetics. Basically, whenever a proponent of alternative medicine uses the word “epigenetics” or “quantum” to explain how an alternative medicine treatment “works,” what he really means is, “It’s magic.” This is a near-universal truth, and even the most superficial probing of such justifications will virtually always reveal magical thinking combined with an utter ignorance of the science of quantum mechanics or epigenetics.
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Posted in: Clinical Trials, Diagnostic tests & procedures, Homeopathy, Medical Academia

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A Skeptical Look at Screening Tests

I’m going to follow Mark Crislip’s example and recycle my presentation from The Amazing Meeting last week, not because I’m lazy or short on time (although I am both), but because I think the information is worth sharing with a larger audience.

We’ve all had screening tests and we’re all likely to have more of them, but there is a lot of misinformation and misunderstanding about what screening tests can and can’t do. Screening tests are done on populations of asymptomatic people and must be distinguished from diagnostic tests done on individual patients who have symptoms. Some tests are excellent for diagnostic purposes but are not appropriate for screening purposes.

We’re constantly being admonished to get tested for one thing or another. A typical example was a recent Dear Abby column. She got a letter from a woman who had been screened for kidney disease and learned that she had a mild decrease in kidney function. Abby was shocked to learn that 26 million Americans have chronic kidney disease, and she advised her readers to get their kidneys checked. This was terrible advice. It superficially seems like good advice, because if you have something wrong with your kidneys, you’d want to know about it, right? In fact, if there was anything wrong anywhere in your body, you’d want to know about it. By that logic, it might seem advisable to test everyone for everything. But that would be stupid. It would find lots of false positives, it would create anxiety by picking up harmless variants and anomalies that never would have caused problems, it would be expensive, and it would do more harm than good.
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Posted in: Cancer, Diagnostic tests & procedures

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Meet Your Microbes: uBiome Offers New Service

We are not alone. Walt Whitman didn’t know how right he was when he said, “I contain multitudes.” The microbes on and in our bodies outnumber our own cells 10:1.  Perhaps that creeps you out. Perhaps that makes you curious to know just who all these billions of creatures are that are using your body for a home and a transportation device.

For just $89 you can learn what’s in your gut, nose, mouth, skin, genitals…or sample anything!

The offer comes from uBiome, a “citizen science startup” that has scientific goals somewhere down the line, but for the moment is happy to just provide a personal service, to sequence your microbiome and tell you how you compare to others. The current utility of this offering is questionable. It’s just not ready for prime time. (more…)

Posted in: Diagnostic tests & procedures, Medical Ethics

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Will Your Smartphone Become a Tricorder?

The Star Trek universe is a fairly optimistic vision of the future. It’s what we would like it to be – an adventure fueled by advanced technology. In the world of Star Trek technology makes life better and causes few problems.

One of the most iconic examples of Star Trek technology is the medical tricorder. What doctor has not fantasized about walking up to a sick patient, waving a handheld device over them, and then having access to all the medical information you could possibly want. No needle sticks for blood tests, no invasive tests, scary MRI machines, and no wait. The information is available instantly.

It’s clear that we are heading in that direction as technology progresses, but how close are we?

The Smartphone in Medicine
Many people in developed nations today are walking around with supercomputers in their pocket – their smartphone. Technological advances are often strange – the ones we anticipate seem to never come, but then life-changing technology creeps up on us.

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Posted in: Diagnostic tests & procedures, Medical devices, Science and Medicine

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Too Much Information!

Some people would like to manage their own health care without having to depend on a doctor. They consult Google, diagnose themselves, and treat themselves. The Do-It-Yourself trend in lab tests continues apace. Without a doctor’s order, patients can get legitimate and/or questionable lab tests directly from various companies such as Any Lab Test Now and Doctor’s Data (which has sued Stephen Barrett for exposing their fraudulent “urine toxic metals” test on Quackwatch). Now a new company, Talking20, has jumped on the self-testing bandwagon with an innovative product that allows people to prick their finger, put a drop of blood on a card, and mail it in from anywhere in the world. Multiple tests are done on a single drop of blood. Results will be available online within a week or even sooner.
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Posted in: Computers & Internet, Diagnostic tests & procedures, Science and the Media

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Once more into the screening breach: The New York Times did not kill your patient

One of the more depressing things about getting much more interested in the debate over how we should screen for common cancers, particularly breast and prostate cancer, is my increasing realization of just how little physicians themselves understand about the complexities involved in weighing the value of such tests. It’s become increasingly apparent to me that most physicians believe that early detection is always good and that it always saves lives, having little or no conception of lead time or length bias. Sadly, just last week, I saw another example of just this phenomenon in the form of an article written by Dr. George Lombardi entitled My Patient, Killed By The New York Times. The depth of Dr. Lombardi’s misunderstanding of screening tests permeates the entire article, which begins with his recounting a story about a patient of his, whose death he blames on The New York Times. After describing the funeral of this 73-year-old man who died of prostate cancer, Dr. Lombardi then makes an accusation:

This one filled me with a special discomfort as I knew a secret: He didn’t have to die. I knew it and he had known it. Had he told?

About 5 years ago he had just retired and had a lot more time on his hands. He was a careful man, lived alone, considered himself well informed. He got into the habit of clipping articles on medical issues and either mailing them to me or bringing them in. They came from a variety of sources and were on a variety of topics. He wasn’t trying to show me up. He was genuinely curious. I kidded him that maybe he’d like to go to medical school in his retirement. ‘No’ he laughed, ‘I just like to be in the know.’

When he came in for his physical in 2008 he told me he’d agree to the DRE but not the PSA (his medical sophistication extended to the use of acronyms: DRE stands for digital rectal exam where I feel the prostate with my gloved finger for any abnormality and PSA for prostatic [sic] specific antigen which is a blood protein unique to the prostate and often elevated in prostate cancer). He had read that the use of PSA as a screening test was controversial. This was the year that the United States Preventive Services Task Force, a government panel that issues screening guidelines, recommended against routine PSA screens for older men. It was often a false positive (the PSA was elevated but there was no cancer), led to unnecessary biopsies, and besides most prostate cancers at his age were indolent and didn’t need to be treated. I countered that prostate cancer was the second leading cause of cancer deaths in men and that it was better to know than not to know. This way it would be our decision. The patient with his doctor deciding what was best. But no, he wanted to stick to his guns and since the DRE was normal no PSA blood test was sent.

After describing a conversation with the man’s daughter, who said, “My father was killed by The New York Times,” Dr. Lombardi then goes on to anecdotal evidence and a cherry-picked publication to support his view, quoting an oncologist who says he’s “seeing more men presenting with advanced prostate cancer” and then referring to a single paper in the current Annals of Internal Medicine about PSA screening. Before I look at the article and a recently published paper on screening mammography that made the news, I can’t help but point out that I (mostly) agree with Dr. Lombardi when he says:

Public health doctors, policy experts and journalists tend to look at the population as a whole. It is a better story if it is one story. It makes a better headline. Their statistics are people I sit across from everyday trying to figure out what the future holds. We each have our job to do.

The problem is, of course, that Dr. Lombardi takes that observation and draws the wrong conclusion, namely that his patient died because of lack of screening. He attacks a straw man, sidestepping the true argument, namely that evidence shows that PSA screening probably causes more harm than good for men at average risk of prostate cancer. Unfortunately, Dr. Lombardi obviously does not understand some very basic concepts behind cancer screening, nor does he apparently recognize that doctors who deal with the population-level data that we have regarding screening tests and try to apply them to individual patients are actually looking in a very systematic way about what the benefits of screening are to the individual patient. More on that later. In the meantime, although I wouldn’t go quite as far as Dr. John Schumann did in criticizing Dr. Lombardi, I do view his lament as a jumping off point to look at some recent data on screening for the two most common cancers, breast and prostate.

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Posted in: Cancer, Diagnostic tests & procedures, Politics and Regulation, Public Health, Science and the Media

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