Six-Year Results From a Phase I/II Trial for Hypofractionated Accelerated Partial Breast Irradiation Using a 2-Day Dose Schedule. (October 2018)

• Record Type: Journal Article
• Authors: Wilkinson, John B.; Chen, Peter Y.; Wallace, Michelle F.; Shah, Chirag S.; Benitez, Pamela R.; Martinez, Alvaro A.; Vicini, Frank A.
• Is Part Of: American journal of clinical oncology. Volume 41:Number 10(2018)
• Publication Date: 2018-10
• Subjects: accelerated partial breast irradiation -- APBI -- hypofractionation -- breast cancer -- brachytherapy; Cancer -- Treatment -- Periodicals; Oncology -- Periodicals; Tumors -- Periodicals; 616.994005
• DOI: 10.1097/COC.0000000000000402
• Languages: English
• ISSNs: 0277-3732

Abstract

Abstract : Background: To report 6-year outcomes from a phase I/II trial using balloon-based brachytherapy to deliver APBI in 2 days. Methods: A total of 45 patients with early-stage breast cancer received adjuvant APBI in 2 days with high-dose rate (HDR) brachytherapy totaling 2800 cGy in 4 fractions (700 cGy BID) using a balloon-based applicator as part of a prospective phase I/II clinical trial. All patients had negative margins and skin spacing ≥8 mm. We evaluated toxicities (CTCAE v3) as well as ipsilateral breast tumor recurrence (IBTR), regional nodal failure (RNF), distant metastasis, disease-free survival, cause-specific survival, and overall survival. Results: Median age and tumor size were 66 years old (48 to 83) and 0.8 cm (0.2 to 2.3 cm), respectively. Four percent of patients were N1 (n=2) and 73% were estrogen receptor (ER) positive (n=32). Median follow-up was 6.2 years (2.4 to 8.0 y). Nearly all toxicities at 6 years were grade 1 to 2 except 1 instance of grade 3 telangiectasia (2%). Eleven percent (n=5) of patients had chronic asymptomatic fat necrosis whereas asymptomatic seromas were noted on mammogram in 13% of cases (n=6). Cosmesis at last follow-up was good or excellent in 91% of cases (n=40) and fair in 9% (n=4). Two of the previously reported rib fractures healed with conservative measures. There were no IBTR or RNF (6 y IBTR/RNF rate 0%); however, 2 patients experienced distant metastasis (4% at 6 y). The 6-year actuarial disease-free survival, cause-specific survival, and overall survival were 96%, 100%, and 93%, respectively. Conclusions: Hypofractionated 2-day APBI using brachytherapy resulted in excellent clinical outcomes with acceptable chronic toxicities.