Abstract 14248: The Impact of Trastuzumab on the Pulmonary Artery Systolic Pressure in Patients With HER-2 Positive Breast Cancer

Abstract

Introduction: Despite that trastuzumab (TZB) improves life expectancy and prognosis in patients with HER-2 positive breast cancer (BC), cardiotoxicity is a well-established complication. However, other potential cardiac complications of TZB such as pulmonary hypertension (PHTN) are poorly investigated. Aim: Evaluate the effect of TZB on pulmonary artery systolic pressure (PASP) and measure the predictors of developing elevated PASP. Methods: The medical records for all females who received TZB treatment for confirmed HER-2 positive BC at King Hussein Cancer Centre in Jordan between 2014 - 2019 who had a documented normal PASP of ≤35 mmHg before treatment were evaluated. Results: A total of 436 patients with a mean age of 53±11 years were included. The leading comorbidities were hypertension and diabetes mellitus affecting 26.2% and 15.4% of the patients, respectively. 15.6% of the study’s population were active smokers. Prior to initiating TZB, 22.3% had left ventricular hypertrophy (LVH), 14.3% had mild tricuspid valve regurgitation (TR), 11.5% had pericardial effusion, and 4.8% had mild aortic valve regurgitation (AR).Of alarming significance, 24.8% of the patients had their PASP increased after one year. Patients who developed elevated PASP tend to be older (56.9 vs 51.3, P<0.001), had baseline mild TR (26.3% vs 10.3%, P<0.001), LVH (39.4% vs 17.6%, P<0.001), and mild AR (9.1% vs 3.7%, P=0.031).Multivariate analysis showed that the only predictors of elevated PASP are TR at baseline (OR 3.9; 95% CI 1.58-6.17, P=0.001), and age (OR 1.04; 95% CI 1.01-1.06, P=0.005). However, baseline LVH (OR 1.79; 95% CI 0.98-3.26, P=0.057), number of the TZB cycles (OR 0.93; 95% 0.85-1.02, P=0.152), and the total dose of TZB (OR 1; 95% CI 1-1, P=0.284) were non-significant predictors. At 1 year follow up, the mean total cumulative dose of TZB was 6.8±1.8 grams that were given at a mean of 15±3 cycles. Moreover, major events (heart failure exacerbation, pulmonary embolism, and acute coronary syndrome) were recorded in 3.9% of the patients and death occurred in 4.1%. Conclusions: Trastuzumab demonstrated an increase in the PASP in a considerable portion of the patients at 1-year interval with this elevation being substantially concerning due to being highly indicative of PHTN.