Incidence of long-term cardiotoxicity and evolution of the systolic function in patients with breast cancer treated with anthracyclines

Background: Anthracycline cardiotoxicity (AC) may manifest years after treatment (long-term cardiotoxicity). There is little data on the incidence and natural history of AC in the current context, with protocols including lower anthracycline doses. The present study prospectively evaluated the incidence, time of occurrence and clinical correlates of long-term cardiotoxicity and the evolution of systolic function in patients with breast cancer treated with anthracyclines.

Methods: This study prospectively included 85 consecutive patients undergoing chemotherapy (CHT) with anthracyclines without trastuzumab. All patients underwent evaluation at baseline, at the end of CHT, 3 months after the end of CHT and 1 and 4 years subsequent to the beginning of CHT. Clinical data and echocardiographic parameters were evaluated in all examinations.

Results: The mean dose of doxorubicin used was 243.53 mg/m2. Median follow-up of the current cohort was 4.5 years. At 1 year the incidence of AC was 1% and at the end of the follow-up 16.5% (14 of 85 patients). Therefore, the incidence of late cardiotoxicity (after the first year) was 15%. Of these 14 patients with AC, 12 had asymptomatic systolic dysfunction, 1 had heart failure and 1 suffered sudden death. Fifteen percent developed systolic dysfunction during follow-up. An early decline in strain was observed in patients who developed long-term AC.

Conclusions: The incidence of long-term cardiotoxicity in patients treated with low-cumulative dose of anthracyclines is high, 16.5% at 4.5 years. This was observed in almost all cases after the first year of follow-up. Therefore, long-term monitoring may be advisable.