Evaluation of the incidence and of risk factors associated with trastuzumab-associated cardiac toxicity in routine clinical practice

589 Background: Data on trastuzumab-associated cardiac toxicity (TACT) in routine clinical practice are scarce. Alcohol is a potential cardiotoxic but it has not been evaluated as a potential risk factor for TACT. Methods: This is a single institution retrospective study, conducted at the Centre des Maladies du Sein Deschênes-Fabia, Quebec City. Charts review was used to collect information on tumor, cardiovascular risk factors (coronary artery disease (CAD), heart failure, high blood pressure (HBP), obesity, diabetes), alcohol (yes/no), smoking (yes/no), type chemotherapy, anthracyclines doses, trastuzumab doses and left ventricular ejection fraction (LVEF). A questionnaire about smoking and use of alcohol (before chemotherapy, during chemotherapy and during trastuzumab alone) was administered to patients. TACT was defined as a decrease in the LVEF of ≥15% or ≥10% with a resulting LVEF < 50% or any follow-up LVEF of < 45%. Results: Data were collected on 117 patients with non-metastatic breast cancer who started adjuvant trastuzumab between 2002 and 2007. Questionnaires on alcohol use/smoking were administered to 61 patients from these 117 patients. Median age was 53 years old and 95.7% received anthracyclines-based chemotherapy. Median follow-up of LVEF was 16.3 months. TACT developed in 25.6% of patients (10.3 % with a decreased in the LVEF of ≥15%, 7.7% with a decreased in the LVEF of ≥10% with a resulting LVEF < 50% and 7.7% with a LVEF < 45%). None of the following risks factors for TACT were significant (using logistic regression): age (p =0.95), CAD (p = 0.29), HBP (p = 0.46), body mass index (p = 0.64), diabetes (p = 0.29), smoking (p = 0.9), anthracycline doses (p = 0.12), baseline LVEF (p = 0.26). Alcohol use was not associated with TACT (p = 0.76). Further data will be collected in next months about alcohol use. Conclusions: In routine clinical practice, TACT was observed in 25.6% of patients, which is higher than what was reported in trastuzumab phase III clinical trials. Results about alcohol use and TACT will be updated in the spring 2009. [Table: see text]