Thursday, January 6, 2011

Colorectal Cancer: What's the best way to screen?

Depending upon how you run the numbers, heart disease & cancer are neck & neck for the top spot as the number one cause of death in the US.  As of this past September, colorectal cancer ranked as the 3rd highest number of new cancer cases & cancer deaths in both men & women.  I mention this bit of background because to a great extent, colorectal cancer deaths should be preventable with appropriate screening.  Our US Preventive Services Task Force strongest "A" recommendations offer a choice between fecal occult blood testing, sigmoidoscopy, or colonoscopy in adults 50-75 years old.  But given a choice, the question always comes up, which is best?

In a case control study published this week, the authors concluded that a colonoscopy w/polypectomy performed with the past 10 years lowered the risk of colorectal cancer by 77% after comparing 1,688 cases with 1,932 controls.  Just this past May, researchers followed for over 11 years 112,939 participant controls & 57,099 who underwent flexible sigmoidoscopy and noted a 23% reduction in colorectal cancer and 31% reduction in mortality.  191 persons needed to be screened to prevent one colorectal cancer diagnosis while 489 needed to be screened to prevent one colorectal cancer death.

Of the stool-based screening methods, immunochemical fecal occult blood testing was considered superior to traditional quaiac-based fecal occult blood testing in two separate studies published last November & last March.  The earlier study from last spring then went on to conclude that flexible sigmoidoscopy was superior to either fecal occult blood tests.  However, to paraphrase former US Surgeon General Dr. C. Everett Koop, any screening test for cancer can't work if you won't take it.

So what's the best way to screen for colorectal cancer?  Any way that you're willing.