Late cardiac morbidity of adjuvant radiotherapy for early breast cancer – A population-based study

Abstract

PurposeThe purpose of this study was to assess the long-term cardiac morbidity and mortality after breast irradiation using contemporary irradiation techniques. MethodsWe used the Catastrophic Illness dataset from the National Health Insurance Research Database to explore the possible association between late cardiotoxicity and women with early breast cancer treated with breast conservation therapy from 2000 to 2010. The Cox proportional-hazards model was used to compare breast cancer patients who received adjuvant radiotherapy versus without adjuvant radiotherapy for the end points with the following primary diagnoses (International Classification of Diseases, 9th Revision codes): ischemic heart disease (410–414, 36.0, 36.1), valvular heart disease (394–397, 424, 35), congestive heart failure (428, 402.01, 402.11, 402.91), and conduction abnormalities (426, 37.7–37.8, 37.94–37.99). ResultsThree hundred and thirty patients received adjuvant radiotherapy and 4802 patients did not receive radiotherapy. Median follow-up was 3.5 years. There was no difference in overall morbidity and mortality from any cardiac cause (p=0.13) in breast cancer patients who received adjuvant radiotherapy versus without radiotherapy by using modern radiotherapy techniques. ConclusionThere were no significant differences in cardiac morbidity and mortality after radiotherapy for breast cancer with a 9-year follow-up period in our population.