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William J. Gradishar, MD, FACP, FASCO


ASTRO 2022: Phase III Trial Compares 3 Versus 6 Weeks of Radiation Therapy for Early-Stage Breast Cancer

By: Victoria Kuhr, BA
Posted: Monday, November 7, 2022

The phase III randomized NRG Oncology/RTOG 1005 trial of a concomitant boost with hypofractionated whole-breast irradiation appears to result in noninferior in-breast recurrence compared with a sequential boost after conventional whole-breast irradiation in high-risk cases—and reduces the overall treatment time. Additionally, Frank A. Vicini, MD, FASTRO, of Michigan Healthcare Professionals, Farmington Hills, and colleagues reported no observable differences in toxicity or cosmetic outcome between the regimens. These findings were presented at the 2022 American Society for Radiation Oncology (ASTRO) Annual Meeting (Abstract 1).

“Three weeks of radiation after lumpectomy is just as effective [as 4 to 6 weeks] for patients who have a higher risk of recurrence as it is for lower-risk patients,” said Dr. Vicini in an ASTRO press release. “As a result, recurrence rates are going down as success rates are going up.”

The study analyzed patients with stage 0, I, and II breast cancer who had an elevated risk of local recurrence after lumpectomy. The patients were randomly assigned to conventional whole-breast irradiation plus a sequential boost daily in arm I or hypofractionated whole-breast irradiation plus a concomitant boost daily in arm II.

A total of 2,262 of 2,354 patients screened were included in the study. Of them, 1,124 were treated in arm I and 1,138 were treated in arm II. Additionally, 34% of patients had stage II breast cancer. The patients had a median age of 55. A total of 81% received three-dimensional conformal radiation therapy and 19%, intensity-modulated radiation therapy. With a median follow-up of 7.3 years, there were 56 in-breast recurrence events. Of the 5- and 7-year in-breast recurrences, 2.0% and 2.2% occurred on arm I and 1.9% and 2.6% occurred on arm II.

No differences in adverse events were reported between the arms. There were low rates of > grade 3 treatment-related adverse events. Of these adverse events, 3.3% occurred on arm I and 3.5% occurred on arm II.

Disclosures: Dr. Vicini reported no conflicts of interest.

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