Completion of colorectal cancer screening in women attending screening mammography

The American Cancer Society (ACS) and the United States Preventive Services Task Force (USPSTF) recommend colorectal cancer (CRC) screening to begin at age 50 in individuals at average risk for CRC. To estimate rate at which women eligible for CRC screening at the time of screening mammography attendance later completed in CRC screening, we retrospectively evaluated CRC screening utilization in women who underwent screening mammography at our institution.

We retrospectively identified 3357 women between the ages of 50 to 75 who received screening mammography in 1998 at a single academic medical center using the institution's Radiology Information System (RIS). Additional information collected from the institution's Health System Data Warehouse and the Radiology department's mammography quality assurance data included mammography results, Breast Imaging Reporting and Database System (BI-RADS) classification of mammography findings, recommendation for screening mammography follow-up, insurance status, and CRC screening utilization after screening mammography. After excluding women who were current with CRC screening at the time of mammography, we determined the proportion of eligible women who completed CRC screening after mammography. Age, insurance type, BI-RADS code, and recommendation code were evaluated as potential predictors of CRC screening completion in eligible women.

Of the 3357 women between the ages of 50 and 75 who received screening mammography in 1998, only 414 (12.3%) were current with CRC screening at the time of screening mammography. Of the remaining 2943 women who were eligible for CRC screening at the time of screening mammography, 142 (4.8%) subsequently completed CRC screening. Average time to completion of CRC screening after screening mammography is 35.4 months (range, 0.27-64.9). Managed care insurance was the only significant predictor of CRC screening completion after screening mammography in eligible women after adjusting for other variables (adjusted OR 1.73, 95% CI 1.21-2.47, P < .0001). Neither BI-RADS classification nor postmammography recommendations were significantly associated with CRC screening completion.

Prevalence studies have demonstrated that women who were compliant with screening mammography were more compliant with CRC screening. Our data suggest that despite this increased compliance, overall incidence of CRC screening is low in the screening mammography population.