A Japanese prospective multi-institutional feasibility study on accelerated partial breast irradiation using multicatheter interstitial brachytherapy: clinical results with a median follow-up of 60 months.

BACKGROUND: We carried out the first multi-institutional prospective study on accelerated partial breast irradiation (APBI) via multicatheter interstitial brachytherapy in a shorter period for early breast cancer in Japan. METHODS: Patient eligibility criteria included positive hormone receptors, tumors ≤ 3 cm and TNM stage pN0M0. After breast-conserving surgery (Japanese cylindrical resection) and histological confirmation of negative surgical margins and the absence of lymph node metastasis, applicator implantation was performed either postoperatively or intraoperatively. High-dose-rate brachytherapy of 36 Gy in 6 fractions was delivered. RESULTS: Forty-six patients from six institutions received this treatment regimen, and the median follow-up time was 60 months (range 57-67 months). The median resected breast tissue volume was 81 cm3 (range 28-260 cm3). No Grade 4 late sequela, local recurrence nor death due to breast cancer were observed. Grade 2-3 sequelae such as rib fracture (2%), soft tissue necrosis (9%), fibrosis (20%), and breast pain (9%) were observed. The resected breast tissue volumes of the patients who had Grade ≥ 2 fibrosis and Grade < 2 fibrosis were 105.9 ± 32.3 cm3 and 76.3 ± 45.6 cm3, respectively, p = 0.02. The overall cosmetic outcome score of Excellent/Good was 74% at 60 months after APBI. Grade ≥ 1 fibrosis was observed in 44% and 92% of patients who scored Excellent/Good and Fair/Poor, respectively, p = 0.004. CONCLUSIONS: This study showed excellent local control and survival results with minimal late sequelae.

Case report of a dose-volume histogram analysis of rib fracture after accelerated partial breast irradiation: interim analysis of a Japanese prospective multi-institutional feasibility study.

We initiated the first multi-institutional prospective study of accelerated partial breast irradiation for early breast cancer in Japan. Our early clinical results showed that the treatment methods were technically reproducible between institutions and showed excellent disease control at a median follow-up of 26 months in our previous report. At present, total 46 patients from six institutions underwent the treatment regimen from October 2009 to December 2011, and the median follow-up time was 60 months (range, 57-67 months). In 46 patients, we experienced one patient who had rib fracture as a late complication. The dose-volume histogram (DVH) result of this patient was analyzed. The D0.01cc, D0.1cc, and D1cc values of the patient were 913, 817, and 664 cGy per fraction, respectively. These values were the highest values in 46 patients. The average D0.01cc, D0.1cc, and D1cc values of the other 45 patients were 546, 500, and 419, respectively, cGy per fraction. From this result, DVH values showing high-dose irradiated volume (D0.01cc, D0.1cc, and D1cc) seem to be a good predictive factor of rib fracture for accelerated partial breast irradiation. However, further investigation is necessary because of the small number of patients investigated.

Uncertainty of cosmetic evaluation after accelerated partial breast irradiation: interim analysis of a Japanese prospective multi-institutional feasibility study.

PURPOSE: We conducted a multi-institutional prospective study on accelerated partial breast irradiation (APBI) using interstitial brachytherapy. The clinical results over a minimum follow-up period of 30 months are presented here. MATERIALS AND METHODS: Forty-six patients with breast cancer were treated with breast-conserving surgery and postoperative APBI. After confirmation of negative surgical margins and negative lymph nodes, a high-dose-rate brachytherapy protocol of 36 Gy/6 fractions was carried out. All clinical data were prospectively collected using the Common Terminology Criteria for Adverse Events ver. 3.0. RESULTS: No recurrence was observed. Cumulative rates of grade 2 or higher late sequelae were 25% for fibrosis, 2% for fractures, 9% for pain, and 9% for soft tissue necrosis. Rates of excellent or good cosmetic results as assessed by the physician and patient were 93 and 89% at the 12-month follow-up and 76 and 74% at the 30-month follow-up, respectively. Large volumes of resected tissue in small breasts were associated with fibrosis of grade 2 or higher. CONCLUSION: APBI in Japanese women provides satisfactory clinical results except for cosmetic outcomes. There is some difficulty with the assessment of fibrosis and cosmetic outcomes, especially in patients with small breasts. CLINICAL TRIAL REGISTRATION NUMBER: UMIN000001677.

A Japanese prospective multi-institutional feasibility study on accelerated partial breast irradiation using interstitial brachytherapy: clinical results with a median follow-up of 26 months.

BACKGROUND: A Japanese prospective multi-institutional feasibility study on accelerated partial breast irradiation using interstitial brachytherapy was performed. The first clinical results were reported with a median follow-up of 26 months. PATIENTS AND METHODS: Forty-six female breast cancer patients with positive hormone receptors and tumors ≤3 cm, pN0M0, completed the protocol treatment. After breast-conserving surgery and histological confirmation of negative surgical margins and pN0, brachytherapy applicators were implanted either postoperatively (n = 45) or intraoperatively (n = 1). High-dose-rate brachytherapy of 36 Gy/6 fractions was delivered. All clinical data were prospectively collected using case report forms and the Common Terminology Criteria for Adverse Events ver.3.0. RESULTS: At the median follow-up of 26 months, no breast cancer recurrence of any type was observed. Sequelae ≥G2 were dermatitis (G2, 7 %), fibrosis (G2, 11 %; G3, 4 %), fracture (G2, 2 %), pain (G2, 7 %; G3, 2 %), and soft tissue necrosis (G2, 6 %). Cosmetic outcomes evaluated by excellent/good scores were 100 % at pre-therapy (n = 46), 94 % at 12 months (n = 46), and 81 % at 24 months (n = 36), respectively. CONCLUSIONS: Disease control and sequelae were satisfactory due to the strict eligibility and protocol-defined treatment parameters. The cosmetic outcomes were comparable to those of previous Japanese breast-conserving therapy series.

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

BACKGROUND: 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. 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. METHODS: For 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 cm(3), 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. RESULTS: Half 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 cm(3) (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. CONCLUSIONS: This study showed that multi-institutional ISBT-APBI treatment plan was reproducible for small breast patient with closed cavity.