Randomized Phase 3 Trial: Partial- vs Whole-Breast Irradiation in Patients With Early Breast Cancer

The phase 3 Danish Breast Cancer Group Partial Breast Irradiation Trial showed noninferiority of partial-breast irradiation to whole-breast irradiation when it comes to risk for breast induration for women who are at least 60 years of age with node-negative early breast cancer undergoing breast-conserving surgery. The open-label, multicenter trial randomly assigned 865 evaluable patients between 2009 and 2016 to either external-beam partial-breast irradiation (n = 431) or whole-breast irradiation (n = 434) with a dose of 40 Gy in 15 fractions. Incidence of grade 2 or 3 breast induration at 3 years was the primary endpoint of the study.

The median follow-up was 5 years for induration and 7.6 years for locoregional recurrence. Results showed that overall induration risk was 12% for those who had whole-breast irradiation compared with 8% for those who had partial-breast irradiation at 5 years (odds ratio [OR] = 0.59, 95% CI = 0.43–0.82). Patients with large breasts compared with small breasts had a heightened risk of induration at 5 years (12% vs 7%; OR = 1.71, 95% CI = 1.23–2.38, P=.001).

Increased risk of dyspigmentation, telangiectasia, edema, or pain was not linked to partial-breast irradiation. In the whole-breast irradiation and partial-breast irradiation groups, excellent or good cosmetic outcome was reported by 85% and 89% of patients. There was no considerable difference seen in locoregional recurrence risk. In the whole-breast irradiation group, 5-year risk was 0.7% (95% CI = 0.2%–1.9%) and in the partial-breast irradiation group, 5-year risk was 1.2% (95% CI = 0.4%–2.6%) (P=.47).

Reference: 

Stenger M. Breast Induration Risk With Partial- vs Whole-Breast Irradiation After Breast-Conserving Surgery for Node-Negative Early Disease. The ASCO Post. Published August 16, 2022. Accessed August 30, 2022. https://ascopost.com/news/august-2022/breast-induration-risk-with-partial-vs-whole-breast-irradiation-after-breast-conserving-surgery-for-node-negative-early-disease/

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