Comparison of Number of Fractions of Accelerated Partial Breast Irradiation
Posted: Tuesday, December 22, 2020
A viable treatment option for patients with favorable-risk early breast cancer is accelerated partial breast irradiation. Randomized trials have previously compared whole-breast radiotherapy with accelerated partial radiotherapy. In a recent multi-institutional trial, led by Vishesh Agrawal, MD, of NewYork-Presbyterian/Weill Cornell Medical Center, and colleagues, three versus five fractions of prone accelerated partial breast irradiation were compared. Their findings, which were presented during the virtual edition of the 2020 American Society for Radiation Oncology (ASTRO) Annual Meeting (Abstract 1078), suggest that breast and skin toxicity were comparable between the two fractions.
“To our knowledge, this is the largest prospective cohort of external-beam partial breast irradiation treated with three versus five fractions,” the investigators reported. “Our early data suggest that accelerated partial radiotherapy with three or five fractions is feasible and well tolerated.”
The participants included 176 postmenopausal women with pathologic T1N0 invasive breast cancer or ductal carcinoma in situ (grade 1 to 2 < 2 cm); all patients completed breast-conserving surgery. Patients were randomly assigned to one of two arms: five fractions daily of 6 Gy (arm 1) or three fractions every other day of 8 Gy (arm 2). For 2 years, acute toxicity was measured and compared between the cohorts.
The most common grade 1 to 2 toxicity was dermatitis, affecting 23 and 16 patients in arms 1 and 2, respectively. Additionally, grade 1 to 2 pain/edema occurred in six participants in arm 1 and 9 participants in arm 2. Of 34 patients who were evaluable at year 2, one patient from arm 1 and two patients from arm 2 experienced grade 1 fibrosis; one participant from arm 1 developed grade 1 telangiectasia; and one participant from arm 2 experienced grade 1 hyperpigmentation. No grade 3 skin or breast toxicities were observed, although this study is ongoing.
Disclosure: For full disclosures of the study authors, visit redjournal.org.