Whole-breast Radiotherapy With Boost for Node-negative Breast Cancer: Conventional vs. Hypo-fractionation.

Objective: Many breast cancer patients receive adjuvant radiotherapy. Tumor bed boost may reduce risk of local failure in high risk patients. We compared hypofractionated whole-breast irradiation (WBI) plus boost (HF+boost) and conventionally fractionated WBI plus boost (CF+boost).

Methods: One-hundred-and-twenty-eight patients receiving HF-WBI (40 Gy in 15 fractions) plus boost (group A) were matched to 127 patients receiving CF-WBI (50.4 Gy in 28 fractions) plus boost (group B), utilizing 10 characteristics.

Results: Grade ≥2 dermatitis rates were 16.4% in group A vs. 44.1% in group B (p<0.0001), and grade ≥2 pneumonitis rates were 1.6% vs. 2.4% (p=0.68). Four-year rates of local control, metastases-free survival, and overall survival were 100% vs. 99% (p=0.81), 98% vs. 100% (p=0.29), and 98% vs. 100% (p=0.17), respectively.

Conclusions: HF+boost was associated with significantly less grade ≥2 dermatitis with similar disease control and survival.