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Cardiotoxicity in breast cancer patients receiving trastuzumab with or without prior anthracycline-based chemotherapy: A prospective study from a tertiary cancer institute at Guwahati, India

Background: Trastuzumab (Herceptin) is used in human epidermal growth factor receptor-2 (HER2)-positive breast cancer patients either alone or in combination with various chemotherapeutic agents in the neoadjuvant, adjuvant as well as palliative settings. Cardiotoxicity remains an issue of concern with the use of trastuzumab which may be enhanced with the prior use of anthracycline-based chemotherapeutic agents. Aim: This prospective study was conducted with the aim of identifying the occurrence of cardiotoxicity in patients receiving trastuzumab with or without a history of prior use of anthracycline-based chemotherapy. Materials and Methods: The study was conducted over a period of 1½ years. All the HER2-positive breast cancer patients who received trastuzumab-based therapy in adjuvant as well as maintenance settings and the cardiotoxicity in terms of drop in left ventricular ejection fraction (LVEF) from the lower limit of normal range were evaluated. A significant drop is defined when LVEF drop is >10%. Cardiotoxicity was compared between those who received prior anthracycline-based chemotherapy versus nonanthracycline-based chemotherapy. Results: A total of 62 HER2-positive breast cancer patients who fulfilled the inclusion and exclusion criteria were enrolled for analysis. Thirty-two patients received prior anthracycline-based chemotherapy and 30 patients received nonanthracycline-based chemotherapy. A significant drop in LVEF of >10% was found in 20 out of 62 patients (32.3%). This significant drop in LVEF was found more in those patients who received prior anthracycline-based chemotherapy (n = 15) versus who did not receive prior anthracycline-based chemotherapy (n = 5) (46.9% vs. 16.7%; P = 0.0109). Conclusion: Trastuzumab-induced cardiotoxicity (LVEF drop >10%) is higher among breast cancer patients who received prior anthracycline-based chemotherapy as compared to those who did not receive prior anthracycline. This clinically significant drop in LVEF warranted an interruption in the treatment till stabilization and improvement of the cardiac function.