Efficacy of Single-plane Implant Technique in Partial Breast Brachytherapy in Small-breasted Patients: Single-plane implant in partial breast brachytherapy

Abstract Purpose Partial-breast irradiation (PBI) using multicatheter-interstitial brachytherapy (MIB) has been supported by some randomized trials to date. However, it remains underutilized in Asian countries because of the population’s typically smaller breasts. Single-plane implantation has been recommended in these individuals, but limited data on the clinical efficacy exist. We performed a retrospective chart review to compare the tumor control and long-term cosmesis in patients treated with the single-plane implant technique. Material and methods Patients receiving MIB-PBI between October 2008 and December 2018 were evaluated. PBI was initiated on the same day of the surgery via an intraoperative catheter implant, delivering 32 Gy by eight fractions. Tumor control based on the rate of freedom from ipsilateral tumor recurrence (IBTR) and disease-free survival and long-term cosmesis using the Harvard scale were evaluated to compare between the single- and double-/triple-plane implant techniques. Results Five hundred sixteen patients with 526 lesions received MIB-PBI with a median follow-up of 53.1 months. Patients treated by single- and double-/triple-plane implant numbered 288 (54.8%) and 238 (45.2%), respectively. The four-year probabilities of IBTR-free survival and disease-free survival were 97.5% and 96.5% in single-plane implant and 98.6% (p = 0.42) and 98.0% (p = 0.18) in double-/triple-plane implant MIB-PBI, respectively. Although young age (p Discussion Although this was a retrospective study from a single institution and cosmesis was evaluated using a subjective method, this is the first report to validate single-plane implant MIB-PBI for use in small-breasted patients. Further multicenter research is required.