Accelerated partial breast irradiation using intensity-modulated radiotherapy technique compared to whole breast irradiation for patients aged 70 years or older: subgroup analysis from a randomized phase 3 trial.

The purpose of this study was to report the efficacy and the safety profile on the subset of selected early breast cancer (BC) patients aged 70 years or older from a single-center phase 3 trial comparing whole breast irradiation (WBI) to accelerated partial breast irradiation (APBI) using intensity-modulated radiation therapy technique. Between 2005 and 2013, 520 patients aged more than 40 years old were enrolled and randomly assigned to receive either WBI or APBI in a 1:1 ratio. Eligible patients were women with early BC (maximum diameter 2.5 cm) suitable for breast conserving surgery. This study is registered with ClinicalTrials.gov, NCT02104895. A total of 117 patients aged 70 years or more were analyzed (58 in the WBI arm, 59 in the APBI arm). At a median follow-up of 5-years (range 3.4-7.0), the ipsilateral breast tumor recurrence (IBTR) rate was 1.9 % in both groups. No significant difference between the two groups was identified (log-rank test p = 0.96). The 5-year disease-free survival (DFS) rates in the WBI group and APBI group were 6.1 and 1.9 %, respectively (p = 0.33). The APBI group presented significantly better results in terms of acute skin toxicity, considering both any grade (p = 0.0001) and grade 2 or higher (p = 0.0001). Our subgroup analyses showed a very low rate and no significant difference in terms of IBTR, using both WBI and APBI. A significant impact on patients compliance in terms of acute and early late toxicity was shown, which could translate in a consistent improvement of overall quality of life.

RCT Entities:   Population Interventions Outcomes