Cardiotoxicity associated with trastuzumab in normal clinical practice

To evaluate the incidence of cardiotoxicity associated with treatment with trastuzumab in clinical practice by describing its characteristics, progress and associated risk factors.

Retrospective observational study of patients with HER2-positive breast cancer treated with trastuzumab in the fi rst quarter of 2007 in a tertiary hospital. Follow-up was performed from start of treatment until the end of March 2008. The data sources used were the oncological computer program Oncowin® from the pharmacy department and the patient clinical history. We gathered variables related to patient baseline characteristics, treatment and safety.

The study included 61 patients. 19 women (32.8%) presented cardiotoxicity, which was the second most common adverse affect of those frequently attributed to the treatment. The average time for toxicity to appear was 7 months, with an average FEVI decrease of 15.6 +/- 9.1 points. In 63.2% of the patients it was symptomatic, and its most frequent manifestation was stress-induced dyspnoea, with a single case of congestive heart failure. Cardiotoxicity led to suspension of treatment in 22.9% of the total patients, which was definitive for 7 out of the 14 patients who interrupted the treatment. No statistically significant differences were found for the possible risk factors.

The incidence of cardiotoxicity in clinical practice is much higher than expected. The important clinical implication of this information and the increasing use of trastuzumab mean that there is a new challenge for the optimal treatment of HER2-positive breast cancer.