Cardiovascular risk in long-term survivors of breast, prostate, colon, and rectal cancer.

BACKGROUND Cardiovascular disease (CVD) is the leading cause of non-cancer mortality in long-term cancer survivors. Population-level assessment of cancer-related exposures is limited with respect to long-term cardiovascular risk in older survivors, who have additional aging-related risks. METHODS This was a SEER-Medicare retrospective cohort study of long-term (five-year) survivors of breast, prostate, colon, and rectal cancers who were aged 66+, diagnosed from 2003-2012, and received definitive treatment. The primary endpoint was late CVD, defined as MI, stroke, CHF/cardiomyopathy on an inpatient administrative claim or as SEER cause of death occurring 5-15 years post-diagnosis. Restricted mean survival time regression was used to assess predictors of shorter average time without CVD and develop a prediction rule for risk stratification. Survivors were assigned a risk score and stratified into tertiles. RESULTS Included were 95,100 survivors with a mean age of 74 (SD = 6) at diagnosis. Late CVD occurred in 23.2% of survivors. Older age, comorbidities, and prior CVD were associated with shorter time without CVD. In contrast, cancer-related factors were not associated, except for stage III breast cancer, and radiation plus ADT for prostate cancer. Across all cohorts, the high-risk strata had a 3- to 4-fold higher risk of CVD compared to the low-risk strata. CONCLUSIONS In this cohort of older, long-term cancer survivors, cancer-related exposures were not independently associated with onset of CVD 5-15 years after diagnosis but may still contribute to latent cardiovascular risk. Given the limited impact of cancer-specific factors, cancer-agnostic risk prediction may be adequate to predict individual cardiovascular risk.