Regular mammography use is associated with elimination of age-related disparities in size and stage of breast cancer at diagnosis

Background: There is little consensus about recommending mammography for women 75 years of age and older. These women have mammography less frequently and are more likely to receive a diagnosis of advanced breast cancer. Objective: To examine the relationship between use of screening mammography and size and stage of cancer at diagnosis in older women. Design: Retrospective cohort study. Setting: Tumor registries in the Surveillance, Epidemiology, and End Results (SEER) program. Patients: 12 038 women who were Medicare beneficiaries, were at least 69 years of age, resided in a SEER area, and received a new diagnosis of breast cancer in 1995 through 1996. Measurements: Screening mammograms obtained in the 2 years before breast cancer diagnosis (none, one, or at least two) and stage and size of tumor at diagnosis. Results: Older women (≥75 years of age) had larger tumors at diagnosis and were less likely to have undergone screening mammography than younger women (69 to 74 years of age). The association between increased mammography use and smaller tumor size and stage was significantly greater in older women than in younger women (P = 0.010 for stage; P = 0.001 for size). The percentage of regular mammography users who received a diagnosis of high-stage disease (28% vs. 26%; P > 0.2) and the mean size of the tumors (15.0 mm vs. 15.1 mm; P > 0.2) did not significantly differ between younger and older women, respectively. These findings remained constant after controlling for factors that might contribute to biases. Conclusion: Mammography in older women is associated with elimination of age-related disparities in size and stage of breast cancer at diagnosis.