Long-term Cosmetic Outcomes and Toxicities of Proton Beam Therapy Compared With Photon-Based 3-Dimensional Conformal Accelerated Partial-Breast Irradiation: A Phase 1 Trial

Local failure rates of 3-dimensional APBI and PBT were similar in this study. However, PBT, as delivered in this study, led to higher rates of long-term telangiectasia, skin color changes, and skin toxicities. We recommend the use of multiple fields and treatment of all fields per treatment session or the use of scanning techniques to minimize skin toxicity.