Safety of adjuvant trastuzumab for HER-2-overexpressing elderly breast cancer patients: a multicenter cohort study

For targeting anti-HER-2, trastuzumab-incorporated chemotherapy is the standard for HER-2-overexpressing breast cancer in adjuvant settings. But there are few data on trastuzumab in elderly patients. We evaluated the incidence of adverse events among an elderly population of trastuzumab-treated HER-2-positive breast cancer patients in adjuvant settings. Data on 39 elderly HER-2 overexpressing breast cancer patients treated with both curative surgery and adjuvant trastuzumab were retrospectively collected from a Japanese multicenter study. The loading dose was 8 mg/kg body weight, and the maintenance dose was 6 mg/kg every 3 weeks; or the loading dose was 4 mg/kg followed by 2 mg/kg weekly as maintenance. After a median follow-up of 20.0 (2.4-53.9) months, a total of 32 patients (82.1%) completed 1-year trastuzumab treatment. The median treatment duration was 12.0 months (range 2-12; mean 10.5). Adverse events occurred in 11 patients (28.2%). Four (10.2%) discontinued or interrupted treatment after experiencing toxicity. One patient died because of interstitial pneumonia. Three patients (7.7%) had congestive heart failure (CHF), one of whom had a history of angina. Three patients (7.7%) had a lower left ventricular ejection fraction (LVEF), and brain natriuretic peptide elevation was totally observed in three patients (7.7%). Three patients with lower LVEF had received chemotherapy containing doxorubicin before trastuzumab. Of the three patients, two discontinued therapy because of CHF, but all recovered with proper medication containing a diuretic agent. Elderly patients tolerated trastuzumab well, although careful management is needed.