Cardiac risk associated with the receipt of anthracycline and trastuzumab in a large nationwide cohort of older women with breast cancer, 1998-2005

To determine the risk of cardiotoxicities in association with trastuzumab with/without anthracycline-containing chemotherapy in a large nationwide population-based cohort of patients with breast cancer. We studied 47,806 women with breast cancer ages >= 65 in 1998-2005 from 16 cancer registries in the Surveillance, Epidemiology and End Results (SEER)-Medicare data and 16,092 cases matched with equal number of controls on the propensity of receiving chemotherapy or trastuzumab. Cumulative incidence of congestive heart failure in year-1 was 5.5% for patients receiving anthracycline and trastuzumab and 3.2% for those receiving anthracycline without trastuzumab. The cumulative incidence of congestive heart failure in year-5 was 15.5 and 9.1%, respectively. Compared to those without chemotherapy and trastuzumab, patients treated with anthracycline-containing chemotherapy and no trastuzumab were 19% significantly more likely to develop congestive heart failure (hazard ratio = 1.19, 95% CI = 1.05-1.34), whereas those receiving trastuzumab without anthracycline and those receiving both trastuzumab and anthracycline were 1.97 and 2.37 times more likely to develop congestive heart failure after adjusting for patient and tumor characteristics. Concurrent or sequential use of anthracycline and trastuzumab was associated with a greater risk of congestive heart failure and cardiomyopathy. Carefully monitoring cardiac functions in patients receiving anthracycline and trastuzumab is warranted.