Early Breast Cancer Treatment and Cardiac Events: A Systematic Review.

Cancer-treatment induced cardiovascular diseases are a concern in early breast cancer, especially when radiation is involved and systemic treatments may contribute. Our primary objective was to estimate the frequency of cardiac adverse events after early breast cancer treatment. We performed a systematic review on cardiac events after early breast cancer treatment, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, by searching PubMed, Scopus and Web of Science and cross-checking references from international guidelines on breast cancer treatment and cardio-oncology. Eighty-one studies were selected. Reporting of cardiac events and dose parameters was heterogeneous among studies due to the variability of the events being considered, follow-up duration and patient's age (most reported less than 5% with some as high as 34% at a maximum follow-up of 28 years). The most frequent are ischemic and valvular heart disease. Radiation modalities (hypofractionation, boost, partial or nodal irradiation) do not seem to change the risk of cardiac events. Anthracycline and aromatase inhibitors increase long-term cardiac risk, whereas anti-HER2-related effects are mostly transient. Myocardites with immunotherapy are rare (<1%) but follow-up is short. Other chemotherapy agents and poly(adenosine-diphosphate-ribose)-polymerase inhibitors have not been shown to increase cardiac risks which is reduced with more recent treatments, and increased by young age at diagnosis and previous cardiac risk factors. Advances in treatment seem to lower cardiac events. Prospective studies with exhaustive reporting of toxicity and radiotherapy features are warranted as well as the help of a cardio-oncologist to manage risk factors.