Randomized prospective trial comparing two schedules of hypofractionated adjuvant radiotherapy 3 weeks against 1 week fractionation regimen in females with breast cancer

Abstract

Purpose Acceleration of radiotherapy in five fractions for breast cancer can improve treatment accessibility, especially in low, middle-income countries and during pandemics. We report on acute toxicity after whole breast irradiation/chest wall irradiation±nodal irradiation, radiotherapy interruption and reported acute pneumonitis with an ultra-hypofractionation schedule compared to modest hypofractionation protocol during the coronavirus disease pandemic. Patients and methods Acute toxicity assessment using the RTOG acute toxicity scoring system. One of two specified doses was administered to the breast: 15 × 2.67 Gy (40.05 Gy) or 5 × 5.2 Gy (26 Gy), tumor boost when indicated prescribed dose 5 × 200 Gy with three-dimensional conformal radiotherapy technique. Inclusion criteria were: T1–T3 invasive breast cancer, N0–N1 and N2 after breast conserving or modified radical surgery. Results A total of 101 patients were included in the study. Median age was 53 ± 10.29 years, with median follow-up time 14 months (12–20 months). A significant difference was observed for acute skin toxicity after radiotherapy in favor of better tolerability for the ultrafractionation schedule (P<0.0001). None of the cases in ultra-hypofractionation had interrupted radiotherapy course for more than 2 days, on the other hand, 45.8% of the cases in modest hypofractionation had interrupted course with chest infection as the second most common cause. Regarding acute radiation pneumonitis none of the cases in both arms reported grades 3–4 acute radiation pneumonitis within the first 90 days postradiotherapy. Conclusion Regarding initial toxicity and patient adherence to the radiation course, this single institute study suggests that hypofractionated breast irradiation in 15 fractions compares favorably to accelerated breast radiotherapy in five fractions over 5 days. However, a longer time for follow-up and larger enrolled numbers are needed to confirm noninferiority of this approach.

Keywords

• breast cancer; coronavirus disease pandemic; radiation pneumonitis; three-dimensional conformal radiotherapy; ultra-hypofractionated radiotherapy