Risk of Lymphedema After Sentinel Node Biopsy in Patients With Breast Cancer.

Purpose: Although numerous studies have identified potential risk factors for ipsilateral lymphedema development in patients with breast cancer following axillary node dissection, the risk factors for lymphedema in patients undergoing sentinel node biopsy without axillary dissection remain unclear. In this study, we aimed to determine the real-world incidence and risk factors for lymphedema in such patients.

Methods: We conducted a single-center, retrospective review of medical records of patients with breast cancer who underwent sentinel node biopsy alone. The development cohort (5,051 patients, January 2017-December 2020) was analyzed to identify predictors of lymphedema, and a predictive model was subsequently created. A validation cohort (1,627 patients, January 2014-December 2016) was used to validate the model.

Results: In the development cohort, 49 patients (0.9%) developed lymphedema over a median follow-up of 56 months, with most cases occurring within the first three years post-operation. Multivariate analysis revealed that a body mass index (BMI) of 30 kg/m² or above, radiation therapy (RTx), chemotherapy, and more than three harvested lymph nodes significantly predicted lymphedema. The predictive model showed an area under the curve of 0.824 for systemic chemotherapy, with the number of harvested lymph nodes being the most significant factor. Patients were stratified into four risk groups, showing lymphedema incidences of 3.3% in the highest-risk group and 0.1% in the lowest-risk group. In the validation cohort, the incidences were 1.7% and 0.2% for the highest and lowest risk groups, respectively.

Conclusion: The lymphedema prediction model identifies RTx, chemotherapy, BMI ≥ 30 kg/m², and more than three harvested lymph nodes as significant risk factors. Although the overall incidence is low, the risk is notably influenced by the extent of lymph node removal and systemic therapies. The model's high negative predictive value supports its application in designing tailored lymphedema surveillance programs for early intervention.