Making better decisions to prevent colon cancer

Colorectal cancer mortality rates (per 100,000) are as much as six times higher in red counties than in those colored dark blue. (Source: NCI SEER data 2007-2011)

To prevent deaths from colon cancer, the U.S. Preventive Services Task Force now recommends no less than eight different screening approaches for average-risk individuals, beginning at age 50.

There is no definitive evidence that one program is superior to another, but they all depend on access to high-quality colonoscopy, which is far from guaranteed, says David Lieberman, M.D., a professor of medicine and head of the Division of Gastroenterology and Hepatology at Oregon Health & Science University. And some screening programs require adherence to multiple steps to be effective, says Lieberman, co-author of a new review of colon cancer screening in the Journal of the American Medical Association. The writers propose that quality should be monitored closely in any screening program recommended in a primary care setting.

Although screening programs based on stool testing probably result in fewer invasive colonoscopies, stool tests are not as effective in reducing the incidence of colorectal cancer. For patients aged 50 to 75 years, Lieberman and co-authors note that annual fecal immunochemical testing (FIT) is estimated to reduce colorectal cancer incidence by 47 percent to 72 percent, while colonoscopy every 10 years reduces the incidence by 62 percent to 88 percent. The reverse tradeoff is that colonoscopy is associated with more than 4,000 lifetime colonoscopies per 1,000 screening recipients, whereas an annual FIT program results in about 1,750 colonoscopies per 1,000 screening recipients. Complications may occur in 15 of 1,000 screening recipients in a colonoscopy program, versus 10 of 1,000 in a FIT program. They write:

Each CRC screening program has a unique potential for mortality reduction, incidence reduction, and possible need for colonoscopy as a part of the screening program and based on the risk level of the individual patient… Some patients may be willing to accept a higher lifetime burden of colonoscopy (with attendant risk) for the potential benefit of never developing CRC and never dealing with colon cancer care (surgery, chemotherapy). Other patients may prefer a less invasive approach, which can effectively reduce mortality, but may be less likely than routine colonoscopy to prevent CRC. These elements should be part of an informed decision-making discussion.

Colon cancer is the third most common cause of cancer death among men and women the U.S. But there is shockingly large regional variation in mortality, in part because of sharp differences in the provision of effective screening programs. The cancer is one of the most preventable, and screening has contributed to a steady decline in the incidence since the mid-1980s. Screening makes it possible to detect not only early-stage cancers but also precancerous lesions, which, when removed, may prevent tumors from developing.

One way to improve screening rates, Lieberman and co-authors write, is to offer a variety of screening methods that make it easier for patients to pursue screening based on their personal preferences.



Screening for Colorectal Cancer and Evolving Issues for Physicians and Patients: A Review by David Lieberman, Uri Ladabaum, Marcia Cruz-Correa, Carla Ginsburg, John M. Inadomi, Lawrence S. Kim, Francis M. Giardiello, and Richard C. Wender. JAMA November 22/29, 2016.