Cardiovascular mortality and morbidity burden in successive and age pre-stratified case-control cohorts of breast cancer women. A population-based study

Aims: To assess the existence, components and clinical relevance of cardiac causes of death and cardiovascular (CV) hospitalizations in a population-wide database of patients with breast cancer (BC).

Methods and results: A population-wide database of the Puglia Region, Italy was analyzed, with a prospective comparative design. Three successive closely matched case/control cohorts representing current care in the period 2007-2014 were also stratified according to age to focus specifically on the potential interaction of treatment-related cardiac toxicity and the expected different baseline CV risk profiles.

Results: At 3-year follow-up, in the successive cohorts the incidence of BC-related (7.7, 7.0, 6.5%) and cardiac causes of death, specifically attributed to heart failure (HF, 1.3, 0.5, 0.5%), decreased. Significant mortality hazard ratio (HR) for HF was found in the total population (1.47, 95% CI 1.14-1.90), in particular in the 2007-2009 cohort (1.71, 95% CI 1.19-2.46) and in the 50-69 age group (7.96, 95% CI 2.81-22.55). Results at 5 years confirm the mortality findings, and a significant HR for hospitalizations for HF, non-atrial arrhythmias and ischemic heart disease in the younger than 50 subpopulation pointed to a late expression of toxicity in the youngest BC population.

Conclusions: The incidence of CV causes of death 3 and 5 years after BC diagnosis was very low, even if an excess in risk of death for HF as compared with the control cohort was observed. While younger patients seems to tolerate BC and BC therapy better in the short term, HF mortality and morbidity resulted significantly increased at 5-year follow-up. As the risk for hospitalization for CV reasons increased at 5-year follow-up in particular in women aged less than 50 years, CV monitoring in this subgroup of patients seems mandatory.