Impact of young age on local control after partial breast irradiation in Japanese patients with early stage breast cancer.

Abstract

Partial breast irradiation (PBI) is an alternative to whole breast irradiation (WBI) for breast-conserving therapy (BCT). A randomised phase 3 trial demonstrated that PBI using multicatheter brachytherapy had an equivalent rate of local recurrence, disease-free survival, and overall survival as compared to WBI. However, limited data are available on PBI efficacy for young patients with breast cancer. We evaluated consecutive patients with Tis-2(≤3cm)N0-1 breast cancer who underwent BCT. For PBI, patients received radiotherapy using multicatheter brachytherapy in an accelerated manner with a dose of 32Gy in eight fractions over 5-6days. For WBI, patients received an external beam radiation therapy that was applied to the entire breast with a total dose of 50Gy in fractions of 2Gy for 5weeks. Two hundred seventy-four patients with 278 lesions received PBI; 190 patients with 193 lesions received WBI. Patients aged <50years including 98 women with 99 lesions receiving PBI and 85 women with 85 lesions receiving WBI were selected. Ipsilateral breast tumor recurrence rate was 3.0 and 2.4% by PBI and WBI, respectively (P=0.99). There was no significant difference in 4-year probability of disease-free survival (97.6 and 91.4% for PBI and WBI, respectively; P=0.87). This is the first report of PBI efficacy in young patients in Asia. Although it is a nonrandomized retrospective chart review of a small cohort of patients with a relatively short follow-up period, PBI may be a better option than WBI following BCS in some young patients with breast cancer.