Colon cancer screening targets wrong elders, study finds

By Steve Tokar

Louise C. Walter, MD

Healthy patients age 70 and older who could benefit from colon cancer screening are not being adequately screened, while ill patients are being screened unnecessarily, according to a study of more than 27,000 veteran patients led by researchers at the San Francisco VA Medical Center.

“Putting someone with heart failure or dementia through a colon cancer screening test such as a colonoscopy is problematic, potentially dangerous, and unlikely to benefit the patient – yet that’s exactly what we’re doing,” says lead author Louise C. Walter, MD, a staff physician at SFVAMC and an associate professor of medicine at the University of California, San Francisco. “At the same time, we’re not screening healthy elders.”

In the study, which appears in the April 7, 2009 issue of “Annals of Internal Medicine,” the authors tracked older patients at four VA medical centers around the United States over a two-year period to determine whether they were screened for colon cancer, and then followed the patients for five years or until they died. They found that only 47 percent of healthy elders with life expectancies of five years or more were screened for colon cancer, while 41 percent of elders with severe illnesses and less than five-year life expectancy were screened.

“This goes against colon cancer screening guidelines, which state that physicians should recommend screening to healthy elders with long life expectancy, and not to elders in poor health,” says Walter. “Instead, age was the main predictor of screening. The older you were, the less likely you were to be screened, regardless of your health status.”

The study authors note that people with a life expectancy of five years or less are not likely to benefit from colon cancer screening because as previous studies have shown, mortality rates between screened and unscreened persons do not become noticeable until at least five years after screening.

The authors found that another predictor of screening was the number of visits made to VA clinics. Patients who made more visits were more likely to be screened.

Walter says this pattern leads to a troubling irony. “Who comes to see physicians more often?” she asks. “People who are sick. And so they are recommended for screening, whereas healthy people who are not seeing doctors precisely because they are healthy are not being offered screening – even though they are most likely to benefit.”

Walter recommends several changes to the way older patients are screened for colon cancer. The first is a re-examination of screening guidelines.

“Guidelines are becoming increasingly age-based, as opposed to health or co-morbidity based,” she observes. “We should reverse that trend. Instead of stopping screening at 75 or 80, let’s look at each patient individually. Some elders are quite healthy, and would benefit from screening. Others have severe illnesses. We should focus on treating those illnesses, rather than being distracted by ordering potentially harmful screening tests.”

Walter also urges “more appropriate outreach to healthy patients” for preventive care. “Right now preventive care is opportunistic, while the patient is in the clinic,” she says. “We have to find a way to reach out to healthy people and say, ‘come in for your preventive health visit.’”

Quality-of-care measures for physicians need to be changed as well, says Walter. “Doctors are graded on whether their patients are being screened or not, without patient health being taken into account,” she notes. “Instead, quality-of-care indicators should be designed to encourage physicians to screen healthy people and not sick people.”

Co-authors of the paper are Karla Lindquist, MS, Sei J. Lee, MD, MAS, and Michele A. Casadei, BS, of SFVAMC and UCSF, and Sean Nugent, BA, Tammy Schult, MS, and Melissa R. Partin, PhD, of the Minneapolis (Minn.) VA Medical Center.

The study was supported by funds from VA Health Services Research and Development and the Robert Wood Johnson Physician Faculty Scholars Program.

SFVAMC has the largest medical research program in the national VA system, with more than 200 research scientists, all of whom are faculty members at UCSF.

UCSF is a leading university dedicated to promoting health worldwide through advanced biomedical research, graduate-level education in the life sciences and health professions, and excellence in patient care.