Screening for colorectal cancer saves lives, and now we have even more evidence of this, as Rick and I discuss on PodMed this week, based on two HUGE studies published in the New England Journal of Medicine. So how HUGE are they? One used the Nurses Health Study and the Health Professionals Follow-Up Study of almost 90,000 participants followed for 22 years, while the other followed just over 33,000 subjects for 30 years. Wow! That's a lot of data.
The first study I mentioned examined sigmoidoscopy and colonoscopy for their ability to identify and prevent deaths from colorectal cancer. While these techniques have been employed and been recommended for screening for some time, proof of their efficacy in these times of close examination of health care costs and benefits is welcome. This study recorded whether 88,902 participants had undergone sigmoidoscopy or colonoscopy and for what purpose, over 22 years. During that time 1815 documented cases of colorectal cancer were identified, with 474 deaths from this disease. Additional examination of the actual tumor and molecular characterization was also performed in many of the cases of colorectal cancer, with an eye toward defining those cancers that arise in people who have undergone screening colonoscopy within five years of presentation.
This study found that indeed, both colonoscopy and sigmoidoscopy do reduce deaths from colorectal cancer, with sigmoidoscopy clearly limited to cancers of the distal colon, while colonoscopy confers survival benefits with regard to proximal disease. A couple of the molecular tests revealed tumor characteristics of the faster growing lesions that may help point the way toward clinical utility.
The second study used the Minnesota Colon Cancer Control Study to take a look at the ability of fecal occult blood testing (FOBT) to reduce the risk of dying of colorectal cancer. During the 30 years of follow-up, 732 deaths occurred from the disease. Both annual and biennial screening reduced the risk of colorectal cancer death, predictably, annual slightly more than every other year, with men experiencing more benefit than women with regard to risk reduction. As Rick and I discuss in the podcast, there's lots of reasons to feel good about this data: FOBT technology is improving all the time and most people find it an acceptable means of screening, in contrast to many folks who simply refuse to undergo sigmoidoscopy or colonoscopy. As more molecular tests are developed and deployed, no doubt the detection capability will improve further, and perhaps we'll see even better results regarding colorectal cancer death prevention.
It's also worth noting that once someone has a negative colonoscopy, they probably don't need another for 7-10 years, so I would say to those who've been avoiding it to just suck it up and be done with it. Clearly, those with a family history of the disease or who've had polyps removed need to be more vigilant.
Other topics this week include the benefits of bracing for scoliosis, also in NEJM, antioxidants and mortality in JAMA, and an IOM report and multiple studies in the Journal of Hypertension on the controversy surrounding salt intake and its health impact. Until next week, y'all live well.