Introduction
RTOG 95-17, a Phase II trial to evaluate multicatheter brachytherapy (mCathBrachy) as the sole method of radiation therapy (RT) for Stage I-II breast cancer (BrCa), was the first cooperative group trial in North America to evaluate accelerated partial breast irradiation (APBI) and include patient reported outcomes (PROs). This report presents year-5 toxicity and cosmesis data.
Methods
Following lumpectomy and axillary dissection for invasive BrCa (tumor size <3 cm with 0-3 positive lymph nodes), 100 patients (pts), 98 evaluable, were treated (txed) with mCathBrachy from 1997-2000 with 34 Gy in 10 BID high dose-rate fractions or 45 Gy in 3.5-6 days as a low dose-rate implant to 1-2 cm beyond the lumpectomy bed. PROs and physician reported outcomes of toxicity, cosmesis and tx satisfaction at year-5 are reported here, defined as data submitted 54-78 months after tx.
Results
Grade (G) 1-2 skin toxicity developed in 78% of pts and G3 in 13% (no G4). Tx effects included skin dimpling/indentation (37%), fibrosis (45%), telangiectasias (45%), skin catheter marks (54%), and symptomatic fat necrosis (15%). Breast asymmetry was reported in 73%. Rates of excellent-good cosmesis were similar between PROs (66%) and radiation oncologists (68%). PROs of tx satisfaction at year-5 was 75%.
Conclusion
RTOG 95-17 documents year-5 skin toxicity and tx effects of mCathBrachy APBI which are associated with PROs of good-excellent cosmesis and high tx satisfaction. This emphasizes the importance of PROs when assessing BrCa tx. NSABP B39/RTOG 0413 will allow for definitive comparisons between APBI and whole breast RT.