ASTRO: Hypofractionated Radiation Therapy Safe After Breast Reconstruction

WEDNESDAY, Oct. 2, 2024 (HealthDay News) — For patients undergoing breast reconstruction, a 16-fraction course of hypofractionated postmastectomy radiation therapy (PMRT) is noninferior to a 25-fraction conventional course, according to a study presented at the annual meeting of the American Society for Radiation Oncology (ASTRO), held from Sept. 29 to Oct. 2 in Washington, D.C.

Matthew M. Poppe, M.D., from the Huntsman Cancer Institute at the University of Utah in Salt Lake City, and colleagues enrolled breast cancer patients with unilateral larger tumors (pT3N0) or smaller tumors and invasion of the regional lymph nodes (pT0-2 pN1-2) who were planning delayed or immediate breast reconstruction and PMRT. Patients were randomly assigned to receive 50.0 Gy in 25 fractions (conventional PMRT) or 42.56 Gy in 16 fractions (hypofractionated PMRT), delivered five days per week (422 and 403 patients, respectively). Patients from 209 centers in the United States and Canada were enrolled from 2018 to 2021 and were followed for a median of 4.5 years.

Of the 650 patients who completed reconstruction, 45 and 55 percent had immediate and delayed breast reconstruction, respectively; 59 and 41 percent had implant alone and autologous +/− implant, respectively. The researchers found that the 24-month incidence of reconstruction complications was 14 and 12 percent with hypofractionation and conventional PMRT, respectively (estimated difference, 2.3 percent, which met the noninferiority margin of 10 percent). Regardless of arm, there was a decrease seen in the complication rate with autologous versus implant-only reconstruction (odds ratio, 0.504). There was no significant difference in acute and late toxicity rates between the arms. Three-year local or regional recurrences occurred in 1.5 and 2.3 percent of hypofractionated and conventional patients, respectively.

“The results of this trial show we can safely reduce treatment time for these patients to three weeks, without compromising their reconstruction,” Poppe said in a statement.

Several authors disclosed ties to the biopharmaceutical industry.

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