Comparison of Outcomes of Microsurgical Breast Reconstruction after Premastectomy and Postmastectomy Radiation Therapy.

Background: This study compared complication rates and outcomes between patients who underwent premastectomy radiation therapy (PreMRT) followed by mastectomy with microsurgical immediate breast reconstruction (IMBR) and patients who underwent mastectomy followed by postmastectomy RT (PMRT) then microsurgical delayed breast reconstruction (DBR).

Study design: This is a secondary analysis of a randomized controlled trial (NCT02912312) that randomized patients with breast cancer to receive hypofractionated (40.05 Gy/15 fractions) or conventionally fractionated (50 Gy/25 fractions) regional nodal irradiation (RNI) between August 2018 and August 2022. Demographic, treatment, and outcomes data were collected. The primary outcome was the rate of autologous flap loss. Secondary outcomes included rates of other recipient-site complications.

Results: 144 patients were included: 41 underwent PreMRT with IMBR and 103 underwent PMRT with DBR, including 66 that had tissue expander (TE) placement at the time of mastectomy and 37 who underwent total mastectomy. The median time from mastectomy to DBR was 12.8 months (IQR, 9.7-16.3 months). There were no complete autologous flap losses in either group and rates of other recipient site complications were similar between the groups. Infection at the recipient site occurred in 20% (13/66) of patients in the PMRT group that underwent TE placement, and 9 (14%) required TE explantation because of complications.

Conclusion: PreMRT with microvascular IMBR is associated with a similar complication rate to PMRT with microvascular DBR whilst avoiding complications relating to TE placement and a reduced time to achieve definitive breast reconstruction. A larger randomized clinical trial of PreMRT followed by mastectomy and IMBR is currently underway (NCT05774678).