Long-term outcomes of APBI via multicatheter interstitial HDR brachytherapy: Results of a prospective single-institutional registry

Publication date: Available online 28 October 2017
Source:Brachytherapy
Author(s): Prashant Gabani, Amy E. Cyr, Jacqueline E. Zoberi, Laura L. Ochoa, Melissa A. Matesa, Maria A. Thomas, Jose Garcia, Julie A. Margenthaler, Michael J. Naughton, Cynthia Ma, Souzan Sanati, Imran Zoberi
PurposeLong-term outcome reports of accelerated partial-breast irradiation (APBI) are limited. Here, we report the 10-year outcomes of APBI delivered using multicatheter interstitial implant (ISI) brachytherapy.Methods and materialsPatients with early-stage breast cancer treated with APBI via ISI brachytherapy were enrolled in a prospective registry. Selection criteria included age ≥40 years, ductal carcinoma in situ or invasive tumor ≤3 cm, negative margins (≥2 mm), and negative axillary nodes. 34 Gy in 10 twice-daily fractions was administered to 2 cm of breast tissue surrounding the surgical bed. Toxicity and cosmetic outcomes were collected prospectively.ResultsA total of 175 patients were included. The median followup time was 10.0 years. Ten-year ipsilateral breast tumor control, regional control, freedom from distant metastasis, breast cancer–specific survival, and overall survival were 92.1%, 96.9%, 97.4%, 97.1%, and 81.2%, respectively. High-grade disease was correlated with increase in the rate of ipsilateral breast tumor recurrence. Grade 1 or 2 skin toxicity was present in 44 patients, and Grade 3 skin toxicity was present in only 1 patient. There were no Grade 4 or higher toxicities observed. Thirty-seven patients developed fat necrosis. Dose Homogeneity Index of ≤0.85 and integrated reference air-kerma of >3400 cGycm²/h correlated with higher rates of fat necrosis. There were 115 (66%), 51 (29%), 8 (5%), and 0 (0%) patients having excellent, good, fair, and poor cosmetic outcomes, respectively.ConclusionsAPBI using ISI brachytherapy offers excellent clinical outcomes in appropriately selected patients with excellent cosmetic outcomes and low rates of toxicities such as symptomatic fat necrosis.



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