Partial-breast irradiation versus whole-breast radiotherapy for early breast cancer: A systematic review and update meta-analysis.

PURPOSE

The purpose of this study was to compare the treatment outcomes of partial-breast irradiation (PBI) versus whole-breast radiotherapy (WBRT) in early breast cancer.

METHODS AND MATERIALS

Eligible randomized clinical trials were identified on Medline, Embase, the Cochrane Library, and the proceedings of annual meetings through December 2019. A meta-analysis for local recurrence (LR), overall mortality (OM), and non-breast cancer mortality (NBCM) was conducted. When possible, the outcomes were calculated for 5, 7, and 10 years of followup. A subgroup analysis by PBI technique (brachytherapy [BT], external beam radiotherapy [EBRT], intraoperative radiotherapy [IORT], and mixed) was performed. A p value < 0.05 was considered significant.

RESULTS

Eleven randomized clinical trials with a total of 14,436 patients (7186 PBI vs. 7250 WBRT) were included in the meta-analysis. The odds ratio (OR) for LR in 5 y was 1.46 (95% CI 1.15-2, p = 0.024) for PBI. In the subgroup analysis, no significant difference for LR was observed between PBI and WBRT using BT (p = 0.51), EBRT (p = 0.25), or mixed techniques (p = 0.89). The only subgroup with statistical difference was IORT 3.1 (95% CI 1.2-7.6, p = 0.014). No significant difference in LR was observed with 7 and 10 years among the groups. The OM had no difference at 5, 7, and 10 years of followup for any subgroup. A nonsignificant difference was observed comparing PBI with WBRT for NBCM OR = 1.24 (95% CI 0.98-1.57, p = 0.07). The rates of cardiac death, contralateral breast cancer, and development of second tumor were not significant.

CONCLUSIONS

The LR with PBI is low and similar to WBRT in selected early breast cancer with a longer followup. The subgroup analysis detected a significant difference for LR associated with IORT and no significant difference for BT and EBRT. Our results confirm a nonsignificant difference for OM and NBCM between PBI and WBRT.