Subclinical myocardial damage after anthracycline chemotherapy in Japanese patients with breast Cancer

Background Data on the incidence, timing, and severity of myocardial damage after anthracycline-based chemotherapy (AC) in Japanese patients with breast cancer are limited. Method We evaluated cancer therapy-related cardiac dysfunction (CTRCD) in Japanese women with breast cancer (n = 51) after the first AC according to the definitions of the 2022 European Society of Cardiology onco-cardiology guideline, including assessment of high-sensitivity troponin I (TnI) and B-type natriuretic peptide (BNP) levels. Results CTRCD was detected in 67 % of the patients (3.9 %, 7.8 %, 9.8 %, 43 %, 37 %, 22 %, 20 %, and 9.8 % of patients at 1 week and 1, 2, 3, 6, 9, 12, and 15 months post-AC, respectively) without significant left ventricular ejection fraction reduction (<50 %) and heart failure. Elevated TnI levels (>26 pg/mL) were found in 43 % of patients, and elevated BNP levels (≥35 pg/mL) were observed in 22 % of patients during the follow-up period. Conclusions Approximately two-thirds of the Japanese patients in this study experienced CTRCD, which was frequently observed at 3 or 6 months post-AC. However, all patients with CTRCD were diagnosed with mild asymptomatic CTRCD. Although, these patients were diagnosed with mild asymptomatic CTRCD, careful long-term follow-up will be required.