The Other Side: Outcomes of the Nonradiated Breast in Bilateral Reconstruction With Unilateral Postmastectomy Radiation Therapy.

[PURPOSE] Radiation therapy following implant-based reconstruction (IBR) is known to contribute to increased complication rates and aesthetic challenges, particularly breast asymmetry, which often necessitates additional revision procedures. Previous studies have primarily focused on the radiated breast, but unilateral postmastectomy radiation therapy (PMRT) following bilateral IBR remains an underexplored area. This study aims to quantify the impact of unilateral PMRT on outcomes for both radiated and nonradiated breasts in patients undergoing bilateral IBR.

[METHODS] A single-center retrospective review was conducted on patients who underwent bilateral IBR followed by unilateral PMRT between January 2017 and December 2022. Outcomes between the radiated and nonradiated breasts were compared. Data were gathered on complications, revision procedures, and the need for additional interventions to address aesthetic concerns.

[RESULTS] A total of 167 patients and 334 breasts were analyzed. The cohort had a median age of 46 years (IQR, 40-53 years), BMI of 23.9 kg/m2 (21.2-27.9 kg/m2), and follow-up period of 23.9 months (IQR, 11.0-39.7 months). Most patients (86%) underwent 2-stage reconstruction, and 68.9% had a revision procedure. Capsular contracture was observed in 10.8% of patients, with a significantly higher incidence on the radiated side (9.0% vs 1.8%, P = 0.006). Complications related to wound healing, including seroma, hematoma, skin necrosis, delayed wound healing, and surgical site infection, were similar between sides (all P > 0.05). Notably, 70 radiated breasts required revision, compared to 58 nonradiated breasts (P = 0.18). A skin-reducing breast lift on the nonradiated side was performed in 11% of patients to improve symmetry (P < 0.001). Other interventions, such as fat grafting (17% vs 18%, P > 0.9), capsulectomy (7.2% vs 3.6%, P = 0.2), capsulotomy (13% vs 8.4%, P = 0.3), and latissimus dorsi flap (1.2% vs 0%, P = 0.5), were not significantly different between the 2 groups.

[CONCLUSION] Unilateral PMRT following bilateral IBR significantly impacts aesthetic outcomes of both the radiated and nonradiated breasts. Most patients in this cohort required revision procedures, with a higher frequency occurring on the radiated side, though nonsignificant. This highlights the need for thorough preoperative counseling regarding the potential for asymmetry in patients undergoing bilateral IBR with unilateral PMRT and the likelihood of revision procedures. Improved understanding of these outcomes can better guide clinical planning and patient expectations.