Assessing First and Multiple Reoperations in 23,301 Breast Reconstructions: Immediate Versus Delayed Reconstructions in Women with Breast Cancer

Background: Few studies have compared the risk of reoperation by timing in breast reconstruction surgery after mastectomy. We evaluated the first and total number of reoperations by reconstruction timing in women with breast cancer undergoing primary mastectomy. Methods: A cohort study of 23,301 primary mastectomies in women with breast cancer undergoing either immediate breast reconstruction (IBR) or delayed reconstruction was carried out within Kaiser Permanente between 2010 and 2022. The first reoperation rate was calculated using cause-specific Cox Proportional Hazards Models, while Multiplicative Cox Proportional Hazards Models were used to account for mortality and timing in reoperation. Patients were continuously monitored for death, outcome of interest, loss to follow-up through healthcare membership termination, or study end date (31 December 2022). Results: In total, 78.4% (n = 18,276) of the cohort underwent IBR. The average follow-up time was 5.9 years (±3.8). The following covariates were imbalanced (standardized mean difference [SMD] ≥ 0.20) between IBR and delayed groups: BMI, smoking status, year of mastectomy, bilateral procedures, and reconstruction type. The crude incidence of first reoperation was 33.04% vs. 31.72% in IBR vs. delayed patients and the risk of reoperation was 18% higher in IBR patients (HR = 1.18, 95% CI = 1.12–1.25). There was no difference in the risk of reoperation by timing (p > 0.05) when assessing multiple reoperations. The reoperation risk was the highest for IBR patients who did not complete reconstruction or single-stage reconstruction. In addition, the first reoperation rate of IBR patients was higher in those who underwent expander–implant-based reconstruction. Conclusions: The first reoperation rate was higher in IBR patients compared to those who delayed reconstruction, although we failed to detect a difference for multiple returns to surgery, except in certain subgroups. Assessing reoperation risk by timing among different reconstruction modalities can aid patients in making informed decisions about the type of breast reconstruction to undergo.