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.
I know a woman who is a survivor of colorectal cancer. At one point, doctors had given up hope and put her in hospice, but she failed to die as predicted and was eventually discharged. She continues to suffer intractable symptoms of pain with alternating diarrhea and constipation. I don’t have access to her medical records, but she tells me her doctors have talked about irritable bowel syndrome (IBS) and have also suggested that the heavy doses of radiation used to treat her cancer may have caused permanent damage to her colon. Whatever the cause, her symptoms have seriously interfered with her mobility and her quality of life. Her health care providers have recently recommended questionable treatments in what I think can be construed as using CAM as a dumping ground for difficult patients.
Colonoscopy hadn’t shown any obstruction, but one of her doctors had hypothesized that her symptoms might be due to impaired bowel motility in the irradiated area. She was desperate enough to consider surgery if there was a chance that bowel resection or colostomy might improve her symptoms. She belongs to a large, well-known HMO with a good reputation. She asked her primary HMO physician who thought the idea was plausible and referred her to a surgeon. The first surgeon said surgery was not indicated and referred her to another surgeon on staff. In addition to being board certified in general surgery, the second surgeon was allegedly board certified in something related to CAM (my friend can’t remember his exact words and has been unable to verify any such credentials online).
The surgeon recommended acupuncture, not once but twice. My friend’s husband (who teaches statistics at a nearby community college) told the surgeon that he was fascinated by the challenges of double-blinded studies of acupuncture and that he was aware of no benefits beyond the placebo level. The surgeon then retreated a little and suggested that the primary benefit of acupuncture in treating IBS was the “relaxation” effect.
Everybody knows that colonoscopy is the best test to screen for colorectal cancer and that colonoscopies save lives. Everybody may be wrong. Colonoscopy is increasingly viewed as the gold standard for colorectal cancer screening, but its reputation is not based on solid evidence. In reality, it is not yet known for certain whether colonoscopy can help reduce the number of deaths from colorectal cancer. Screening with fecal occult blood testing (FOBT) and flexible sigmoidoscopy are supported by better evidence, but questions remain. It seems our zeal for screening tests has outstripped the evidence.
Statistics show that the life-time risk for an adult American to develop colorectal cancer (CRC) is approximately 6%. Colorectal cancer is the second leading cause of cancer deaths in the United States. In the US there are currently 146,970 new cases and 50,630 deaths each year. Between 1973 and 1995, mortality from CRC declined by 20.5%, and incidence declined by 7.4% in the United States.
The US Preventive Services Task Force (USPSTF) recommends screening for colorectal cancer (CRC) using fecal occult blood testing, sigmoidoscopy, or colonoscopy, in adults, beginning at age 50 years and continuing until age 75 years. (more…)