Incidence of trastuzumab-induced cardiotoxicity and impact of body mass index in patients with breast cancer: Results from a Saudi tertiary cancer center.

The effect of BMI as a risk factor in trastuzumab-induced cardiotoxicity in Saudi patients with HER2-neu positive breast cancer treated with trastuzumab and anthracyclines is not fully understood. The present study retrospectively evaluated the overall incidence of cardiotoxicity and the effect of BMI as a risk factor for cardiotoxicity. A retrospective study performed between 2011 and 2015 of patients with Her2-neu positive early breast cancer who were treated with either a combination of trastuzumab and anthracycline or a combination of trastuzumab with non-anthracycline or hormonal treatment in the adjuvant settings was carried out. The incidence of cardiotoxicity and the effect of BMI, hypertension and diabetes mellitus as risk factors for cardiotoxicity were assessed. Cardiotoxicity was measured using a drop in the ejection fraction of >10 percentage points to a left ventricular ejection fraction of <50%. The present cohort included 105 patients diagnosed with stage I and II breast cancer. The mean age of the present cohort was 47.5±1.0 years (range, 25-76 years), the mean height was 153.9±14.1 cm (range, 126-170 cm), the mean body weight was 75.7±15.6 kg (range, 40-143 kg) and the mean BMI was 31.3±5.8 (range, 18-49). Cardiotoxicity was detected in 21.9% of the cohort. The BMI was calculated for 81 patients who were treated with a combination of trastuzumab and anthracycline. Cardiotoxicity was detected in 3 out of 9 patients with a BMI <25, in 9 out of 23 patients with a BMI between 25 and 29, and in 6 patients with a BMI >30. There was a significant association between cardiotoxicity and BMI (P=0.03). No significant association between age, hypertension and diabetes and cardiotoxicity was identified. In conclusion, compared with global cohorts, the present results revealed a higher incidence of cardiotoxicity among Saudi patients with HER2-neu positive early breast cancer treated with trastuzumab combinations in adjuvant settings. Increased BMI was significantly associated with cardiotoxicity.