Autologous vs. implant-based breast reconstruction and long-term mental disorder risk: a retrospective cohort study emulating a target trial.

[BACKGROUND] While postmastectomy breast reconstruction is commonly offered to improve quality of life, its long-term psychological impact by reconstruction type remains poorly understood. This study aimed to evaluate the long-term risk of clinically diagnosed mental disorders following autologous reconstruction (AR) vs. implant-based reconstruction (IBR) in breast cancer patients undergoing mastectomy.

[MATERIALS AND METHODS] We conducted a target trial emulation using a nationwide population-based cohort from the Korean National Health Insurance Service (2015-2023), with follow-up up to 9 years after reconstruction. Women newly diagnosed with breast cancer and underwent total mastectomy followed by breast reconstruction were included (N = 24 930). Outcomes were compared by reconstruction type, categorized as AR or IBR. A 1:3 propensity score matching compared 5113 patients undergoing AR and 14 738 receiving IBR. The primary outcome was time to the first diagnosis of any mental disorder, identified using International Classification of Diseases, Tenth Revision, Clinical Modification codes for anxiety, depression, bipolar disorder, post-traumatic stress disorder, sleep disorders, and substance use. Cox proportional hazards models estimated hazard ratios and 95% confidence intervals (CIs), adjusting for demographic and clinical covariates.

[RESULTS] In the matched cohort (mean age 48.7 years), the incidence of any mental disorder was higher in the AR group than in the IBR group [adjusted hazard ratio (aHR) 1.13; 95% CI, 1.07-1.19]. The association was more pronounced in patients aged ≥50 years (aHR 1.16; 95% CI, 1.07-1.26). Time-stratified analyses showed increasing risk over time, persisting through 5 years. Among younger patients (<50 years), delayed AR was associated with lower psychiatric risk (aHR 0.79; 95% CI, 0.57-1.11; interaction P = 0.021). Validation analysis confirmed higher psychiatric risk with radiotherapy, supporting robustness of outcome definitions.

[CONCLUSIONS] AR was associated with an elevated long-term risk of mental disorders, particularly among older patients. These findings underscore the need for age-specific, psychologically informed counseling when discussing reconstruction options in survivorship care.