A Japanese prospective multi-institutional feasibility study on accelerated partial breast irradiation using interstitial brachytherapy: treatment planning and quality assurance.

Yuki Otani,Takayuki Nose,Norikazu Masuda,Ken Yoshida,Yu Kumazaki,Shino Nakagawa,Shuuji Asahi,Naoto Shikama,Masahiko Oguchi,Tadayuki Kotsuma,Yoshio Moriguchi,Eisaku Yoden,Taisei Matsumura,Seiji Tachiiri,Takushi Dokiya,Ichirou Fukuda,Jun Itami,Iwao Tsukiyama,Hiroshi Shinmoto ,Kenichiro Nakashima ,Tsuyoshi Takahashi ,Toshiaki Sendo

doi:10.1186/s13014-015-0430-8

Abstract

BackgroundIn Japan, breast-conserving surgery with closed cavity has generally been performed for breast cancer patients, and accelerated partial breast irradiation (APBI) is considered difficult because Asian females generally have smaller breast sizes than Western females. Therefore, common identification of target and treatment plan method in APBI is required. A prospective multicenter study was conducted in Japan to determine institutional compliance with APBI using high-dose-rate interstitial brachytherapy (ISBT) designed for Japanese female patients.MethodsFor this study, 46 patients were recruited at eight institutions from January 2009 to December 2011. The reproducibility of the ISBT–APBI plan was evaluated using three criteria: (1) minimum clinical target volume dose with a clip dose ≥ 6 Gy/fraction, (2) irradiated volume constraint of 40-150 cm3, and (3) uniformity of dose distribution, expressed as the dose non-uniformity ratio (DNR, V150/V100) < 0.35. The ISBT–APBI plan for each patient was considered reproducible when all three criteria were met. When the number of non-reproducible patients was ≤ 4 at study completion, APBI at this institution was considered statistically reproducible.ResultsHalf of the patients (52 %) had a small bra size (A/B cup). The mean values of the dose-constrained parameters were as follows: Vref, 117 cm3 (range, 40-282), DNR, 0.30 (range, 0.22-0.51), and clip dose, 784 cGy (range, 469-3146). A total of 43/46 treatment plans were judged to be compliant and ISBT–APBI was concluded to be reproducible.ConclusionsThis study showed that multi-institutional ISBT–APBI treatment plan was reproducible for small breast patient with closed cavity.

Highlights

In Japan, breast-conserving surgery with closed cavity has generally been performed for breast cancer patients, and accelerated partial breast irradiation (APBI) is considered difficult because Asian females generally have smaller breast sizes than Western females
Breast-conserving surgery followed by postoperative radiotherapy is the standard of care for early-stage breast carcinoma [3, 4]
This study presents the creative method of clinical target volume (CTV) and dose limitation for Asian females

Summary

Introduction

In Japan, breast-conserving surgery with closed cavity has generally been performed for breast cancer patients, and accelerated partial breast irradiation (APBI) is considered difficult because Asian females generally have smaller breast sizes than Western females. A prospective multicenter study was conducted in Japan to determine institutional compliance with APBI using high-dose-rate interstitial brachytherapy (ISBT) designed for Japanese female patients. Postoperative irradiation by whole-breast irradiation (WBI) reduces the rate of ipsilateral breast recurrence by one-third [4, 5]. Studies have reported that WBI prevents recurrence only near the tumor bed [3, 4, 6]. Localized irradiation of the tumor bed is preferable for patients at a low risk of recurrence

Methods

Results

Discussion

Conclusion