Optimizing the integration of modern systemic therapies and advanced radiotherapy techniques in breast cancer management: An expert opinion from the Institut Curie Breast Radiotherapy Group.

Abstract

The integration of modern systemic therapies with radiotherapy (RT) represents a promising strategy in breast cancer management, enhancing both locoregional control and systemic disease outcomes. This expert consensus from the Institut Curie Breast Radiotherapy Group focuses exclusively on modern systemic agents, synthesizing current evidence on the concurrent administration of human epidermal growth factor receptor 2-targeted agents (trastuzumab, pertuzumab, trastuzumab emtansine, trastuzumab deruxtecan), cyclin-dependent kinase 4 and 6 inhibitors (palbociclib, ribociclib), immunotherapies (pembrolizumab), poly(ADP-ribose) polymerase inhibitors (olaparib), and new antibody-drug conjugates (sacituzumab govitecan). Drawing from extensive clinical experience, including retrospective and prospective studies conducted at Institut Curie, this review provides a comprehensive analysis of the feasibility and safety of these novel combinations, ensuring an evidence-based approach to optimizing breast cancer treatment strategies. In addition to systemic therapy considerations, this review highlights the importance of advanced RT techniques, including proton therapy, isocentric lateral decubitus positioning, and volumetric modulated arc therapy with deep inspiration breath hold, which play a crucial role in minimizing cardiac and pulmonary toxicities, particularly in patients receiving cardiotoxic agents or those with predisposing risk factors. By integrating both systemic advancements and optimized radiation delivery, this review provides a practical framework for the safe and effective combination of modern breast cancer therapies.