Comprehensive evaluation of the incidence of late effects in 5-year survivors of breast cancer

Late effects of breast cancer affect the quality of survivorship. Using administrative data, we compared the occurrence of almost all ICD9 codes among older breast cancer survivors to that among a matched comparison cohort to generate new hypotheses. Breast cancer patients 65 years or older diagnosed 1990-1994 in 6 integrated care settings and who survived at least 5 years were matched with a cohort of women without a history of breast cancer on care setting, age, and calendar time. We collected data on the occurrence of incident ICD9 codes beginning 6 years after the breast cancer diagnosis date and continuing to year 15, and comparable data for the matched woman. We calculated hazard ratios (HRs) and 95 % confidence intervals associating breast cancer survivorship with incidence of each ICD9 code. We used semi-Bayes methods to address multiple comparisons. Older breast cancer survivors had about the same occurrence of diseases and conditions 6-15 years after breast cancer diagnosis as comparable women. The median of 564 adjusted HRs equaled 1.06, with interquartile range 0.92-1.3. The distribution of HRs pertaining to cancer-related ICD codes was shifted toward positive associations, and the distribution pertaining to cardiovascular-related ICD codes was shifted toward negative associations. In this hypothesis-scanning study, we observed little difference in the occurrence of non-breast cancer-related diseases and conditions among older, long-term breast cancer survivors, and comparable women without a history of breast cancer.