Screening mammography rate and predictors following treatment for colorectal cancer

Colorectal cancer survivors remain at risk for breast cancer. Thus, it is important to determine if screening mammography rates are reduced by the diagnosis and treatment of incident colorectal cancer.

Mammography rates among 7,666 67-79 year-old stage 0-III colorectal cancer survivors were compared with rates among 36,433 age-, race/ethnicity-, SEER area-matched women controlling for pre-diagnosis mammography, stage, chemotherapy, income, co-morbidities, treatment in teaching hospital, number of physician visits, and gynecologist visits.

In the first 2 years after diagnosis, the survivors' rate (49.7/100) was 4.2% higher than the controls' (47.6/100), p < 0.001. It was 7.5% higher in the next 2 years, 54.5/100 versus 49.7/100, p < 0.001. The higher rates resulted from significantly greater rates among survivors without prior mammography, 30.9/100, compared with their controls (25.3/100) in the first 2 years, for example (O.R. = 1.23, 95% C.I. = 1.15-1.32). The strongest predictors of post-diagnosis mammography were pre-diagnosis mammography (O.R. = 5.76, 95% C.I. = 5.19-6.38), visiting a gynecologist (O.R. = 1.83, 95% C.I. = 1.55-2.16), chemotherapy (O.R. = 1.61, 95% C.I. = 1.40-1.86), and more than nine physician visits. Increasing Charlson scores and cancer stage were associated with lower mammography rates.

Overall, the competing demands of cancer diagnosis and treatment did not reduce mammography rates, and these events were associated with increased rates among previous non-users.

The low mammography rate among survivors with no history of a prior mammogram means that the physicians treating these women must emphasize the need for such care.