Abstract
Since February, 2008, in Japan, breast cancer patients that overexpress HER2 protein were able to receive trastuzumab as a postoperative adjuvant treatment. Although in Japan the clinical benefits and safety data related to trastuzumab (2 mg/kg weekly) used in relapse therapy have been examined the acceptability of trastuzumab given in a dose of 6 mg/kg triweekly for postoperative adjuvant treatment is still unclear. Therefore, we examined the presence of cardiotoxicity, which is the most noteworthy side effect of trastuzumab, in 26 patients treated with trastuzumab as postoperative adjuvant therapy for 1 year. Twenty-four patients (92.4%) previously received anthracycline-containing regimens which is one of the known cardiotoxic risk factors. No patient developed heart failure, but two patients had asymptomatic cardiotoxicity during the dosing period. In these two patients, cardiac function was restored after trastuzumab administration was terminated ; thus, the cardiotoxicity was reversible. In summary, trastuzumab can be safely given as adjuvant treatment to patients who were previously treated with anthracycline, if their cardiac function is carefully evaluated.
