Colorectal cancer screening behavior in women attending screening mammography: Longitudinal trends and predictors

PURPOSE: Nationally representative surveys demonstrate that the adherence to screening mammography guidelines are associated with increased prevalence of colorectal cancer (CRC) screening; however, the incidence of CRC screening in the screening mammography population is unknown. Our purpose was to describe non-fecal occult blood test (FOBT) CRC screening utilization by women prior to and subsequent to screening mammography at a large academic medical center. MATERIALS AND METHODS: Using the institutional administrative data base, 17,790 women aged 50 and older who underwent screening mammography between 1998 and 2002 were retrospectively identified. We determined that women were current with non-FOBT CRC screening at the time of mammography if they had undergone flexible sigmoidoscopy or double-contrast barium enema in the 5 years or colonoscopy since 1995, the earliest for which data are available. We excluded FOBT as a form of CRC screening because the administrative data base did not adequately capture episodes of FOBT. Women who were not current were considered eligible for non-FOBT CRC screening. We then assessed the number of women who underwent flexible sigmoidoscopy, barium enema, or colonoscopy within 12 months following mammography. Age, insurance status, Breast Imaging Reporting and Data System classification, recommendations after screening mammography and year of mammography were examined as potential predictors of non-FOBT CRC screening completion. RESULTS: At the time of mammography, 13.3% women were current with non-FOBT CRC screening. Of women eligible for non-FOBT CRC screening at the time of mammography, 1.1% completed non-FOBT CRC screening within 12 months after mammography. The rate of non-FOBT CRC screening completion increased over time. After multivariate analysis, being insured by a commercial managed care organization or by Medicaid remained significant predictors of non-FOBT CRC screening. CONCLUSION: The prevalence of non-FOBT CRC screening is low in the population of women undergoing screening mammography, with an incidence of 1.0%. Future studies should examine whether delivering CRC screening interventions at a screening mammography visit increase adherence to non-FOBT CRC screening.