Single-center retrospective study of effectiveness and toxicity of five-fraction prone accelerated partial breast irradiation

A retrospective study at Grossman School of Medicine (New York University) evaluated outcomes of 5-fraction accelerated partial breast irradiation (APBI) among women with early-stage breast cancer. The patients received APBI 600cGy x 5 fx delivered daily (56%) or every other day (44%), mostly in the prone position (92%). A a median follow-up of 48 months, local recurrence was seen in 2.7% of patients. The most common late grade ≥ 2 adverse event was breast fibrosis (6.2%). At a median follow-up of 80 months, the rates of good-excellent physician and patient-rated cosmesis were 95% and 85%, respectively, with no difference betwee patients treated on consecutive days versus every other day. Five-year overall survival, locoregional recurrence-free survival, and disease-free survival were 97.2%, 97.7%, and 89.5%, respectively. The authors conclude that five-fraction APBI either daily or every other day was effective with low rates of local recurrence, minimal toxicity, and excellent cosmesis at long-term follow-up.