Proton-Based Radiotherapy After Breast-Conserving Surgery
Posted: Friday, January 24, 2020
According to a retrospective review of the Rutgers Cancer Institute of New Jersey database presented at the 2019 San Antonio Breast Cancer Symposium (Abstract P4-12-20), postoperative proton-based radiotherapy may lead to improved cosmetic results and less radiation exposure to healthy tissue when compared with photon-based radiotherapy. “We found that proton-based radiotherapy was well tolerated among our patients with a high rate of favorable cosmetic outcomes,” noted Nisha Ohri, MD, of Rutgers Cancer Institute, in a Rutgers Health press release.
The study included 21 patients with breast cancer who had been treated with proton-based radiotherapy after breast-conserving surgery between 2015 and 2019. The median planning target was 94% for V95, 71% for V100, and 2% for V110. Patients experienced a median whole-breast dose of 46.8 Gy, a median maximum point dose of 115%, and a median mean heart dose of 0.39 Gy.
The median patient age at the time of diagnosis was 58 years, and the median patient body mass index was 26.1. A total of 14% of patients had previously undergone adjuvant radiotherapy for ipsilateral breast cancer. More than half of the participants had node-positive disease (71%), T1 primary tumors (52%), and/or left-sided tumors (57%). During treatment, 57% of patients underwent neoadjuvant chemotherapy, and 24% received adjuvant chemotherapy. Lumpectomy boosts of a median dose of 10 Gy were delivered to 81% of patients.
At a median cosmetic follow-up of 27 months, the majority of patients (79%) reported either good or excellent cosmetic results, with the remaining 21% reporting fair cosmetic outcomes. Two patients died prior to the cosmetic follow-up. The treatment was generally well tolerated. Commonly reported adverse events included dermatitis (grade 2, 66%; grade 3, 14%) pain (grade 2, 33%; grade 3, 10%), and fatigue (grade 2, 33%).
Disclosure: For the full disclosures of the study authors, visit abstractsonline.com.
