Intraoperative Open-Cavity Implant for Accelerated Partial Breast Irradiation Using High-Dose Rate Multicatheter Brachytherapy in Japanese Breast Cancer Patients: A Single-Institution Registry Study

Abstract

Background: Previous research has compared the efficacies of accelerated partial breast irradiation (APBI) and wholebreast irradiation (WBI). APBI immediately after surgery may provide more benefit after intraoperative insertion of catheters. Although balloon catheter-based APBI is available in the US, it is difficult in Japanese women, who have relatively small breasts. With the applicators being implanted during tumor removal, APBI can be started immediately after surgery. The aim of this study was to assess the safety and efficacy of APBI using the intraoperative open-cavity implant technique. Method: Patients (age ≥ 40 years) with invasive breast cancer (diameter ≤ 3 cm) were enrolled. Before lumpectomy, the insertion of applicators and delivery doses were simulated by computed tomography (CT). After confirmation of free margins and negative sentinel nodes (SNs) using frozen section analysis, applicators were inserted. Postoperative CT-based dose distribution analysis was performed using dose-volume histograms. APBI was started on the day of surgery, delivering 32 Gy in 8 fractions over the following 5 -6 days, and it covered a distance of 2 cm from tumor margins. This observational study was approved by the institutional review board of our hospital. Results: From October 2008 to July 2012, 157 women (160 lesions) were enrolled (age 55.0 years, <40:9, SN + : 25, for patients' request). The mean number of applicators used was 6.4 (2 -15) and mean planning target volume was 35.8 cm 3 (6.5 -137.1 cm 3 ). All radiotherapy-related toxicities were mild. However, 12 patients (7.5%) experienced wound breakdown because of surgical site infection. Two patients developed ipsilateral breast tumor recurrence (1 marginal, 1 at a distant site). Conclusions: Despite the small number of participants and a short follow-up period, our results suggest that this technique could be helpful in establishing clinical safety and efficacy.

Sentinel-Node-Driven Personalized Radiation Techniques Ranging from Partial Breast Irradiation to Regional Nodal Radiation after Breast-Conserving Surgery

“…Therefore, we previously initiated a prospective observational study of APBI with multicatheter brachytherapy as an alternative to WBI after BCS. Data regarding the long-term efficacy of our technique in Japanese breast cancer patients indicated a few instances of local recurrence and a low rate of adverse events [25,26].…”

“…We initiated a prospective observational study on APBI with multicatheter brachytherapy after BCS. Data regarding the long-term efficacy of our technique indicated a few instances of local recurrence and a low rate of adverse events [26,27]. Therefore, APBI, rather than WBI, is primarily performed in node-negative patients.…”

Individualized Case–Control Study of Accelerated Partial Breast Irradiation by Multicatheter Intertstitial Brachytherapy in Japanese Patients with Breast Cancer

“…A detailed summary and eligibility criteria have been reported previously (Sato et al, 2012). Our criteria included patient age ≥40 years, histologically documented breast cancer, no prior treatment, unifocal disease, maximum tumor diameter ≤3.0 cm, and confirmation of negative margins and sentinel node metastasis using frozen section analysis.…”

“…BCS followed by APBI with multicatheter brachytherapy has previously been reported (Sato et al, 2012;Sato et al, 2011). The procedure involved the insertion of applicators and delivery doses simulated by preoperative computed tomography (CT).…”

“…Four-year follow-up data have been reported showing a few instances of local recurrence and a low level of adverse events (Sato et al, 2012). However, this observational study was based on a retrospective chart review; therefore, it is difficult to validate the procedure because of the small number of included patients, varying clinical backgrounds, and a short follow-up period.…”