Alcohol and HER2 polymorphisms as risk factor for cardiotoxicity in breast cancer treated with trastuzumab.

Background: Trastuzumab has no major side-effects except the potential for cardiac toxicity. The main objective of this study was to evaluate the association between trastuzumab-associated cardiac toxicity and two potential risk factors: alcohol intake and HER2 polymorphisms.

Methods: In a retrospective cohort study of 237 women with non-metastatic HER2-positive breast cancer treated with trastuzumab, traditional risk factors were assessed by review of medical records, alcohol use by an administered questionnaire to women (n=132), and HER2 polymorphisms (Ile655Val and Ala1170Pro) using TaqMan assays (n=73).

Results: Association was observed between alcohol intake (10 drinks and more per week) during the trastuzumab treatment and cardiac toxicity (p=0.04). For polymorphisms, compared to Ile/Ile carriers, HER2 Ile/Val was associated with a higher risk of cardiac toxicity (p=0.02).

Conclusions: Heavy alcohol use during the course of trastuzumab treatment and the HER2 Ile/Val genotype may constitute risk factors for cardiac toxicity.