Association between autoimmune diseases and risk of developing breast cancer-related lymphedema

Preexisting autoimmune disease may increase susceptibility to breast cancer-related lymphedema (BCRL) through chronic inflammation and immune dysregulation, but its association with BCRL risk is poorly understood. We conducted a retrospective cohort study of adults undergoing sentinel lymph node biopsy and/or axillary lymph node dissection for breast cancer at a tertiary cancer center between 2010 and 2021. Autoimmune diseases were identified using International Classification of Diseases (ICD)-9/10 codes, and the primary outcome was BCRL diagnosis based on ICD codes. Associations between autoimmune disease and time to BCRL were evaluated using univariate and multivariable Cox proportional hazards models. Among 20,027 patients with a median follow-up of 61.7 months (IQR, 38.7-94.2), 1361 (6.8%) had a preexisting autoimmune disease and 1728 (8.6%) developed BCRL at a median of 17.4 months (IQR, 8.0-33.9) after surgery. In multivariable analysis, autoimmune disease was independently associated with increased BCRL risk (hazard ratio [HR], 1.52; 95% CI, 1.30-1.77; P < .001). Elevated risks were observed for rheumatoid arthritis (HR, 1.54), autoimmune thyroiditis (HR, 1.40), Graves' disease (HR, 1.49), multiple sclerosis (HR, 1.87), systemic lupus erythematosus (HR, 2.46), and systemic sclerosis (HR, 2.10). These findings suggest autoimmune disease may be an independent risk factor for BCRL and may improve risk stratification.