BACKGROUND: Post-mastectomy radiotherapy (PMRT) after immediate two-stage implant reconstruction (TSIR) has been historically associated with significant risk for complications and implant failure. To address limited data in the modern era, we studied outcomes after PMRT in these patients and identified risk factors for complications. METHODS: This IRB-approved, retrospective study included patients who underwent mastectomy with immediate TSIR followed by PMRT for a unilateral primary breast cancer at our institution from 2012-2021 with ?3 months follow-up. Major reconstruction complications (MRC) were infection requiring washout, capsular contracture (CC) requiring capsulotomy or explantation, implant exposure or rupture, and hematoma/seroma (H/S) requiring surgical drainage. Reconstruction failure (RF) was defined as tissue expander (TE) or permanent implant (PI) removal without immediate replacement. Absolute reconstruction failure (ARF) was defined as RF without further attempts at reconstruction. Logistic regression was used to identify risk factors for MRCs or RF and significant variables were included in a multivariate analysis. RESULTS: 190 patients met criteria for inclusion (median follow-up 29 months). 19.0% experienced an MRC. Individual MRC rates were: infection (5.3%), CC (10.5%), exposure (5.3%), rupture (1.6%), and H/S (1.6%). MRCs were more common in patients who had PMRT to the TE rather than the PI (TE-PMRT) (OR=2.9, p=0.02) and with active smoking (OR=6.3, p=0.02), both of which remained significant on multivariate analysis. RF and ARF occurred in 14.2% and 5.3% of patients respectively. Causes of RF are shown in Table 1. TE-PMRT and active smoking increased the risk of RF (OR=4.0, p=0.01; OR=5.0, p=0.04) and TE-PMRT remained significant on multivariate analysis. Implant infection was strongly associated with RF (OR = 15.4, p < 0.001). CONCLUSION: PMRT in immediate two-stage implant reconstruction at our institution in the modern era carries an acceptably low risk of MRCs and RF. TE-PMRT and active smoking increase the risk for MRCs and RF.
Table 1: Causes of Reconstruction Failure
| PMRT to Tissue Expander (N = 119) | PMRT to Permanent Implant (N = 71) | ||
| Reconstruction Failure Cause | N (%) | Reconstruction Failure Cause | N (%) |
| Infection | 8 (6.7%) | Infection | 1 (1.4%) |
| Capsular Contracture | 4 (3.4%) | Capsular Contracture | 3 (4.2%) |
| Implant Exposure | 5 (4.2%) | Implant Exposure | 0 (0%) |
| Breast Pain | 2 (1.7%) | Breast Pain | 0 (0%) |
| Patient Preference | 2 (1.7%) | Patient Preference | 0 (0%) |
| Radiation Dermatitis | 1 (0.8%) | Radiation Dermatitis | 0 (0%) |
| Multifactorial | 1 (0.8%) | Multifactorial | 0 (0%) |
