Accelerated Partial Breast Not Inferior to Whole-breast Irradiation Following Surgery

Accelerated partial breast irradiation (APBI) using sole interstitial multicatheter brachytherapy in patients with early breast cancer was not inferior to adjuvant whole-breast irradiation, according to results of a phase 3 randomized non-inferiority trial reported in the Lancet.¹

Investigators looked at 5-year local control, disease-free survival, and overall survival to compare APBI with whole-breast irradiation in patients with stage 0, 1, and 2a breast cancer who had undergone breast-conserving surgery.

Between April 20, 2004, and July 30, 2009, a total of 1,184 patients in seven European countries were randomly assigned to receive either APBI (n=633) or whole-breast irradiation (n=551).

A follow-up 5 years later showed that 9 patients treated with APBI and 5 patients treated with whole-breast irradiation had a local recurrence. The cumulative recurrence rate was 1.44% (95% CI, 0.51-2.38) with APBI and 0.92% with whole-breast irradiation (95% CI, 0.12-1.73).

In regard to safety, no grade 4 late side effects were reported and grade 2-3 late side effects to the skin occurred in 3.2% of patients treated with APBI compared with 5.7% of patients treated with whole-breast irradiation (P=.08). Grade 2-3 subcutaneous tissue side effects were reported in 7.6% of patients in the APBI group vs 6.3% in the whole-breast irradiation group (P=.46).

Reference

1. Strnad V, Ott OJ, Hildebrandt G, et al. 5-year results of accelerated partial breast irradiation using sole interstitial multicatheter brachytherapy versus whole-breast irradiation with boost after breast-conserving surgery for low-risk invasive and in-situ carcinoma of the female breast: a randomised, phase 3, non-inferiority trial [published online ahead of print October 19, 2015]. Lancet. doi: 10.1016/S0140-6736(15)00471-7.