Effect of early shoulder functional exercise timing on drainage duration and subcutaneous seroma formation in overweight women undergoing modified radical mastectomy for breast cancer

This retrospective study investigates the impact of early postoperative shoulder functional exercise timing on drainage duration and subcutaneous seroma formation in overweight women undergoing modified radical mastectomy (MRM) for breast cancer. A total of 194 overweight breast cancer patients (BMI > 24) who underwent MRM between January 2023 and December 2024 were included. Patients were divided into a study group (n = 101, shoulder exercise initiated on postoperative day 7) and a control group (n = 93, exercise started on day 3). Key outcomes included postoperative drainage volume, drainage tube retention duration, and incidence of subcutaneous seroma. Additional visual analyses and subgroup analyses by BMI were performed. A multivariable logistic regression model was constructed to identify independent predictors of seroma formation. The study group exhibited significantly lower postoperative drainage volume (229.5 ± 82.2 vs 581.3 ± 115.7 mL, P < .001), shorter drainage tube retention duration (6.8 ± 0.8 vs 8.3 ± 0.7 days, P < .001), and a lower incidence of subcutaneous seroma (11.9% vs 30.1%, χ2 = 8.850, P = .003). Visual comparisons confirmed more favorable distribution patterns in the study group. BMI subgroup analysis revealed that patients with BMI ≥ 27.0 kg/m2 had worse outcomes, and benefited more from delayed exercise. Multivariate analysis identified early exercise initiation (odds ratio (OR) = 4.14, P = .004), higher BMI (OR = 1.20, P = .031), and advanced tumor stage (OR = 1.92, P = .015) as independent risk factors for seroma. Delaying shoulder functional exercise initiation to postoperative day 7 significantly reduces drainage volume, shortens drainage tube retention, and lowers the risk of seroma in overweight women following mastectomy. These benefits are particularly pronounced in patients with higher BMI. Adjusting rehabilitation protocols based on body habitus may improve postoperative recovery and warrants broader clinical adoption.