Trastuzumab (herceptin): a retrospective analysis of the effects of long-term application in a series of patients with breast cancer.

INTRODUCTION: About 20 % of all mamma carcinomas are HER2 positive. The overexpression of HER2 is considered to be a negative prognostic factor. Trastuzumab is a monoclonal anti-HER2 antibody developed to target HER2 overexpressing tumor cells. So far, there is only little data available on long-term effects of trastuzumab. This is why we analyzed the medical records of our patient collective with respect to tolerability and oncological outcomes of long-term trastuzumab treatment. MATERIALS AND METHODS: Our retrospective observational study included all patients of the Saarland University Hospital with breast cancer who received trastuzumab for more than 18 months between 2003 and 2012. We analyzed the medical records with respect to oncological outcome, tolerability and cardiac side effects. RESULTS: A total of n = 15 patients had been treated with trastuzumab for over 18 months with a mean therapy duration of 57.2 months (range 18-119 months). The mean follow-up time was 113.5 months (range 50-240 months). Three of the patients had a treatment interruption for an average of 2.6 months (range 3-5), which was not due to side effects. The left ventricular ejection fraction (LVEF) was controlled at regular intervals in all of the patients. Upon the beginning of the trastuzumab treatment, the mean LVEF was 68 %. In one patient, the trastuzumab treatment was discontinued after 41 months because of a decrease of the LVEF below normal levels. CONCLUSION: Trastuzumab is well tolerated even during long-term use. Patients with HER2 overexpression and metastases can be treated well with trastuzumab for up to 119 months.