Pertuzumab and trastuzumab combination with concomitant locoregional radiotherapy for the treatment of breast cancers with her2 receptor overexpression

Abstract

Background: The combination of pertuzumab and trastuzumab dual HER2 blockade with concomitant curative dose locoregional breast radiotherapy in patients with metastatic breast cancer is an important part of treatment strategy. Methods: This was a retrospective study conducted at the Institut Curie on all patients treated concomitantly with pertuzumab/trastuzumab and locore-gional breast radiotherapy. Toxicity was evaluated according to the NCICTCAEv4.0. Overall sur-vival, progression‐free survival and locoregional recurrence‐free survival were evaluated in meta-static patients who were initially well controlled by chemotherapy, for whom local treatment was decided by the multidisciplinary team. Results: Fifty‐five patients treated between October 2013 and December 2019 were included, with a median follow‐up of 4.1 years. The median age was 53 years (range: 28–81). All patients received curative dose radiotherapy (RT) concomitantly with per-tuzumab and trastuzumab (Pertu/Trastu). The median radiation dose was 50 Gy. Safety evaluation did not reveal any significant adverse effects, with 3 cases of grade 3 radiodermatitis (5.4%), but no significant gastrointestinal or cardiac toxicity. The mean difference in LVEF before any chemotherapy and after radiotherapy was −2.43% (p < 0.01). Conclusions: This study demonstrates that the combination of locoregional breast RT with dual HER2 blockade by Pertu/Trastu was very well tolerated, suggesting that RT can be safely administered to patients with HER2‐positive breast can-cer.