# Breast reconstruction-related complications from postmastectomy radiation therapy in stage II–III breast cancer: sub-analysis of a multi-institutional observational study (Reborn-03)

## TL;DR

This study finds that postmastectomy radiation therapy increases the risk of complications after breast reconstruction, particularly with prosthetic methods.

## Contribution

The study identifies PMRT as an independent risk factor for breast reconstruction complications in stage II–III breast cancer patients.

## Key findings

- PMRT was associated with higher complication rates in prosthetic breast reconstruction.
- No significant difference in complications was found in autologous breast reconstruction with PMRT.
- PMRT was an independent risk factor for breast reconstruction-related complications.

## Abstract

Although postmastectomy radiation therapy (PMRT) is a standard treatment for high-risk breast cancer, it adds the risk of complications after breast reconstruction (BR).

This multi-institutional cohort study included patients with stage II–III breast cancer—defined as tumor size ≥ 5 cm, lymph node involvement, and/or skin/chest wall invasion—who underwent immediate or delayed BR after mastectomy between January 2008 and December 2018. We retrospectively investigated the relationship between PMRT and BR-related complications after adjusting for patient characteristics and BR method.

Among 1138 patients (1101 immediate and 37 delayed BR), 427 (37.5%) underwent PMRT. The cohort included 238 (20.9%) patients with tumors ≥ 5 cm, 725 (63.7%) with 1–3 lymph node metastases, and 257 (22.6%) with ≥ 4. BR methods included 750 prosthetic, 385 autologous, and 3 fat graft procedures. The overall complication rates were 25.2% and 31.5% in the non-PMRT and PMRT groups, respectively (p = 0.028). In prosthetic BR, capsule contracture (p < 0.001) and infection (p = 0.014) were more frequent in the PMRT than the non-PMRT group, whereas no significant difference was observed in complication rates between two groups in autologous BR. Multivariate analysis identified PMRT as an independent risk factor for BR-related complications (odds ratio, 1.47; p = 0.032). The reoperation rate was similar in two groups.

PMRT was associated with an increased incidence of BR-related complications in prosthetic BR, but not with reoperation, irrespective of the reconstruction method.

The online version contains supplementary material available at 10.1007/s12282-025-01799-z.