Study: About Half of U.S. Adults Don't Get Recommended Colorectal Cancer Screening

Despite the proven effectiveness of colorectal cancer screening in reducing the incidence of this disease -- regular colorectal cancer screening is recommended by the AAFP, the U.S. Preventive Services Task Force and the American Cancer Society -- about half of all Americans still don't undergo appropriate screening. That's one of the findings from a study published in the July issue of Cancer Epidemiology, Biomarkers & Prevention. (abstract available for free; nonsubscribers pay $15 for one-day access to the full article)

It's a shortfall FPs can address through greater outreach to their older patients, says one family physician expert.

The study's researchers used data from the 2005 National Health Interview Survey of adults ages 50 and older. Overall, the combined age-standardized proportion of survey respondents who reported having had a fecal occult blood test, or FOBT, within the past year and/or endoscopy within the past 10 years was 50 percent. The proportion of respondents who reported having an FOBT during the past year was 12 percent; the proportion reporting having undergone an endoscopy within the past 10 years was 45.2 percent.

For respondents who had been screened for colorectal cancer using endoscopy, 72.8 percent said that it was part of a routine exam; 24.3 percent underwent the procedure because of a problem. Of those who had been screened using an FOBT, 91 percent said that it was part of a routine exam, while 7.8 percent said it was the result of a problem.

Further analysis of the sociodemographics and health-related characteristics of those who received colorectal cancer screening showed some interesting trends. The subgroups with the highest age-standardized testing percentages were those with a family history of colorectal cancer and those who had military health care coverage; among these groups, slightly more than 68 percent of respondents had been screened. The lowest age-standardized screening rates were seen among individuals who did not have a usual source of health care (24.7 percent), those without health insurance coverage (24.1 percent) and those who had not visited a physician during the past year (19.5 percent).

In addition, the age-standardized proportion of Hispanic respondents who reported appropriate testing was lower than that for non-Hispanics, and the rates for blacks were lower than those for whites. Furthermore, women who reported not having undergone a mammogram within the past two years or a Pap smear within the past three years were less likely to report having had appropriate colorectal cancer screening than those who recently had undergone one of these tests.

Interestingly, when applicable sociodemographic and health-related variables were adjusted for one another, their associations with colorectal cancer screening use were largely attenuated. In particular, the difference between rates of screening among blacks and whites was virtually eliminated.

However, even after this adjustment, health care coverage and having a usual source of health care remained strongly correlated with colorectal cancer test use.

Michael Potter, M.D., a professor in the Department of Family and Community Medicine at the University of California, San Francisco, and a member of the National Colorectal Cancer Roundtable, or NCCRT, said he thinks the results of this study show that outreach to patients older than 50 about colorectal cancer screening needs to be increased.

Perhaps the most important thing that FPs can do for their patients, Potter said, is to remind them that "colorectal cancer is one of the most preventable cancers out there," and that there's a "menu of options" available for all patients, regardless of income level. Endoscopy, while very effective, he added, is only one of a number of tests that patients can undergo.

Potter said he's a firm believer that "the best test is the one you can get the patient to take." Offering endoscopy is important, he said, but an FOBT is a safe, effective alternative that patients can do themselves at home. However, he advised, patients need to know that for this type of testing to be effective, it must be done every year. Unfortunately, Potter notes, "many people have only done it once."

Potter also recommends that FPs use a newly developed resource from the NCCRT, "How to Increase Colorectal Cancer Screening Rates in Practice: A Primary Care Clinician's Evidence-Based Toolbox and Guide." The guide includes information on insurance coverage for colorectal cancer screening, essential elements of increasing screening rates, office reminder systems and communication systems. The guide (130-page PDF; About PDFs) is available from the NCCRT Web site.