The Impact of Premastectomy Versus Postmastectomy Radiation Therapy on Outcomes in Prepectoral Implant-Based Breast Reconstruction
Authors: Sinnott Catherine J. , Pronovost Mary T. , Persing Sarah M. , Wu Robin , Young Anke Ott 
Published: April 2021

Purpose
Prepectoral implant-based breast reconstruction is being increasingly performed over subpectoral reconstruction because of the reduced invasiveness of the procedure, postoperative pain, and risk of animation deformity. Radiation therapy is a well-known risk factor for complications in implant-based breast reconstruction. The effect of premastectomy versus postmastectomy radiation therapy on outcomes after prepectoral breast reconstruction has not been well-defined. The purpose of this study was to compare the impact of premastectomy versus postmastectomy radiation therapy on outcomes after prepectoral breast reconstruction.

Methods
A retrospective chart review was performed on all patients who underwent prepectoral implant-based breast reconstruction with inferior dermal flap and acellular dermal matrix performed by a single surgeon from 2010 to 2019. Demographic, clinical and operative data were reviewed and recorded. Outcomes were assessed by comparing rates of capsular contracture, infection, seroma, hematoma, dehiscence, mastectomy skin flap necrosis, rippling, implant loss, local recurrence and metastatic disease, between patients receiving premastectomy and postmastectomy radiation therapy and nonradiated patients.

Results
Three hundred and sixty-nine patients (592 breasts) underwent prepectoral implant-based breast reconstruction. Twenty-six patients (28 breasts) received premastectomy radiation, 45 patients (71 breasts) received postmastectomy radiation, and 305 patients (493 breasts) did not receive radiation therapy. Patients with premastectomy radiation had higher rates of seroma (14.3% vs 0.2%), minor infection (10.7% vs 1.2%), implant loss (21.4% vs 3.4%) and local recurrence (7.1% vs 1.0%), compared with nonradiated patients (P < 0.05). Patients with postmastectomy radiation had higher rates of major infection (8.4% vs 2.4%), capsular contracture (19.7% vs 3.2%), implant loss (9.9% vs 3.4%), and local recurrence (5.6% vs 1.0%) when compared with nonradiated patients (P < 0.03). Outcomes after prepectoral breast reconstruction were comparable between premastectomy and postmastectomy radiation patients, respectively, with regard to major infection (7.1% vs 8.4%), dehiscence (3.6% vs 1.4%), major mastectomy skin flap necrosis (7.1% vs 2.8%), capsular contracture (10.7% vs 19.7%), implant loss (21.4% vs 9.9%), and local recurrence (7.1% vs 5.6%) (P ≥ 0.184). However, premastectomy radiation patients had a higher rate of seroma compared with postmastectomy radiation patients (14.3% vs 0%; P = 0.005).

Conclusions
In prepectoral implant breast reconstruction, premastectomy and postmastectomy radiation therapy were associated with higher rates of infection and implant loss compared with nonradiated patients. Postmastectomy radiation was associated with a higher rate of capsular contracture compared with nonradiated patients, and a comparable rate of capsular contracture compared with premastectomy radiation therapy patients. Premastectomy radiation was associated with a higher rate of seroma compared with postmastectomy radiation and nonradiated patients.