Use of annual mammography among older women with ductal carcinoma in situ.

BACKGROUND: As ductal carcinoma in situ (DCIS) is a risk factor for invasive breast cancer, ongoing annual mammography is important for cancer control, yet little is known about racial/ethnic and other disparities in use among older women with DCIS.
METHODS: SEER-Medicare data was used to identify women age 65-85 years, diagnosed with DCIS from 1992 to 2005 and treated with surgery, but not bilateral mastectomy. We examined factors associated with receipt of an initial mammogram within 1 year of treatment and subsequent annual mammograms for 3 and 5 years. We examined whether follow-up care, by a primary care physician or cancer specialist, or neighborhood characteristics mediated disparities in mammography use.
RESULTS: Overall, 91.3% of women had an initial mammogram. After adjustment, blacks and Hispanics were less likely than whites to receive an initial mammogram (odds ratio (OR) 0.74, 95% confidence interval (CI) 0.55-0.99 and OR 0.65, CI 0.46-0.93, respectively, as were women of lower socioeconomic status (SES), women who had a mastectomy or breast conserving surgery without radiation therapy, and women who did not have a physician visit. Overall rates of annual mammography decreased over time. Disparities by SES, initial treatment type, and physician visit did not diminish over time. Physician visits had a modest effect on reducing initial racial/ethnic disparities.
CONCLUSIONS: Annual mammography among women age 65 to 85 with DCIS declines as women get further from diagnosis. Interventions should focus on reducing disparities in the use of initial surveillance mammography, and increasing surveillance over time.