Cardiovascular Disease in Males With Breast Cancer: A Population-Based Cohort Study

There are scarce data on cardiovascular disease (CVD) risk in male breast cancer (BC).

The objective of the study was to describe CVD risk in males with BC compared to females with BC and cancer-free males.

Population-based cohort study using linked administrative databases. We identified males diagnosed with BC in Ontario, Canada (1998-2021). Male BC patients were age-matched to 3 female BC and 3 male cancer-free controls. The primary outcome was hospitalization or emergency department visits for CVD. Cause-specific mortality was a secondary outcome. Cause-specific hazards regression was used to estimate HRs associated with male BC status.

We matched 683 males with BC to 2,049 females with BC and 687 males with BC to 2,061 cancer-free males (median age 68 years [IQR: 59-77 years]). Males with BC had more prevalent pre-existing CVD and risk factors than both comparators. After adjusting for baseline characteristics, male BC was associated with a similar risk of CVD hospitalization/emergency department visits compared to female BC (HR: 1.03; 95% CI: 0.86-1.25) and cancer-free males (HR: 1.00; 95% CI: 0.84-1.19). Male BC was not associated with higher CVD mortality but was associated with higher cancer mortality relative to both comparator groups.

Males with BC have greater baseline cardiovascular risk than females with BC and cancer-free males but no increase in future CVD hazard after adjustment. This highlights the need for prioritizing cancer treatment in males with BC, with appropriate attention to CVD risk management.