- Is the Time Right for Five-Fraction Partial Breast Irradiation?. September 08, 2020
DOI: 10.1200/JCO.20.00650 Journal of Clinical Oncology - published online before print August 24, 2020
Accelerated Partial-Breast Irradiation Compared With Whole-Breast Irradiation for Early Breast Cancer: Long-Term Results of the Randomized Phase III APBI-IMRT-Florence Trial
2Azienda Ospedaliero–Universitaria Careggi, Florence, Italy
3Istituto per lo Studio la Prevenzione e la Rete Oncologica (ISPRO), Florence, Italy
4Ospedale Santa Maria Annunziata–Azienda Usl Toscana Centro, Florence, Italy
To report the long-term results of external-beam accelerated partial-breast irradiation (APBI) intensity-modulated radiation therapy (IMRT) Florence phase III trial comparing whole-breast irradiation (WBI) to APBI in early-stage breast cancer.
The primary end point was to determine the 5-year difference in ipsilateral breast tumor recurrence (IBTR) between 30 Gy in 5 once-daily fractions (APBI arm) and 50 Gy in 25 fractions with a tumor bed boost (WBI arm) after breast-conserving surgery.
Five hundred twenty patients, more than 90% of whom had characteristics associated with low recurrence risk, were randomly assigned (WBI, n = 260; APBI, n = 260) between 2005 and 2013. Median follow-up was 10.7 years. The 10-year cumulative incidence of IBTR was 2.5% (n = 6) in the WBI and 3.7% (n = 9) in the APBI arm (hazard ratio [HR], 1.56; 95% CI, 0.55 to 4.37; P = .40). Overall survival at 10 years was 91.9% in both arms (HR, 0.95; 95% CI, 0.50 to 1.79; P = .86). Breast cancer–specific survival at 10 years was 96.7% in the WBI and 97.8% in the APBI arm (HR, 0.65; 95% CI, 0.21 to 1.99; P = .45). The APBI arm showed significantly less acute toxicity (P = .0001) and late toxicity (P = .0001) and improved cosmetic outcome as evaluated by both physician (P = .0001) and patient (P = .0001).
See accompanying editorial on page 4135