Cardiac Toxicity Under Concurrent Administration of Trastuzumab (Anti-HER2 Therapy) and Radiotherapy: Systematic...

Concomitant administration of trastuzumab (Tra) and radiotherapy (RT) has been known as an effective strategy for treating HER2-positive breast cancer (HER2⁺ BC) patients. Studies have investigated the incidence of cardiotoxicity due to this concomitant treatment, but the results are conflicting. This systematic review and meta-analysis study evaluated the cardiac toxicity occurrence in patients undergoing Tra + RT.

A systematic review was conducted on the databases of PubMed, WOS, and Scopus up to 2024. The decline in left ventricular ejection fraction (LVEF) from baseline was assessed as a cardiac toxicity indicator, LVEF reduction Grade 1 (LVEF 60%-50%), Grade 2 (LVEF 50%-40%), and Grade 3 (LVEF 40%-20%).

Seven studies meeting defined criteria were included in this investigation. This study examined the prevalence of LVEF-grade 1-3 in HER2⁺ BC patients undergoing concurrent treatment with Tra and RT. The combined results showed a prevalence of decreased LVEF in Grades 1-3 as 21.4%, 4%, and 1%, respectively, with statistical significance (p < 0.05). Thus, among patients experiencing decreased LVEF, 70% were Grade 1, 25% were Grade 2, and 5% were Grade 3.

Cardiotoxic effects of chemotherapy and RT may accumulate and lead to heart failure so early diagnosis methods are advised. Concurrent RT with Tra is well-tolerated clinically, and coadministration does not significantly raise primary cardiotoxicity. Cardiac toxicity may occur in some patients, requiring long-term follow-up to assess the impact of combining Tra and RT on heart function and its correlation with patient prognosis.