Long-term cardiovascular effects of breast cancer treatment

Breast cancer (BC) is the most common cancer in women. In western countries, implementation of screening and treatment advances have increased 5-year survival rates up to 82%. Though effective, chemo- and radiotherapy may lead to cardiac dysfunction. The aim of this thesis was to study the prevalence and risk of long-term cardiovascular effects in BC survivors. For that, we evaluated a retrospective cohort and conducted a cross-sectional assessment in BC survivors treated with chemotherapy and/or radiotherapy, at least 5 years after diagnosis. In both studies a comparison was made with age- and general practitioner (GP) matched controls. Longterm BC survivors treated with chemo- and/or radiotherapy were at a two times increased risk of developing mild systolic cardiac dysfunction (LVEF<54%; 15 vs. 7%), and cardiovascular diseases were more prevalent among BC survivors: 31% vs. 24% and 14% vs. 7% in the retrospective and the cross-sectional study, respectively. Bias cannot be excluded. Furthermore, we systematically examined the predictive value of cardiac biomarkers measured at time of BC diagnosis and analyzed biomarker profiles to hypothesize on causal pathways of cardiac dysfunction development among survivors. We did not find a useful predictive biomarker. BC survivors treated with chemotherapy and anti-hormonal therapy appeared to have a higher pro-inflammatory and proarteriosclerotic biomarker profile compared to controls. Based on our findings, we cannot formulate a specific cardiac follow-up for women treated for BC. However, because 15% of these women have a reduced cardiac function, maintaining a healthy lifestyle and having cardiac risk factors treated is important