Lymphadenectomy After Melanoma-A National Analysis of Recurrence Rates and Risk of Lymphedema.

INTRODUCTION: Treatment for melanoma after a positive sentinel lymph node biopsy includes nodal observation or lymphadenectomy. Important considerations for management, however, involve balancing the risk of recurrence and the risk of lymphedema after lymphadenectomy.

METHODS: From the Merative MarketScan Research Databases, adult patients were queried from 2007 to 2021. International Classification of Disease, Ninth (ICD-9) and Tenth (ICD-10) Editions, diagnosis codes and Current Procedural Terminology codes were used to identify patients with melanoma diagnoses who underwent an index melanoma excision with a positive sentinel lymph node biopsy (SLNB). Main outcomes were completion lymph node dissection (CLND) utilization after a positive SLNB, developing lymphedema with or without CLND, and nodal basin recurrence 3 months or more after index excision. Subanalyses stratified by index excision year (2007-2017 and 2018-2021) and propensity score matched were additionally conducted. Demographics and comorbidities (measured by Elixhauser index) were recorded.

RESULTS: A total of 153,085,453 patients were identified. Of those, 359,298 had a diagnosis of melanoma, and 202,456 patients underwent an excision procedure. The study cohort comprised 3717 patients with a melanoma diagnosis who underwent an excision procedure and had a positive SLNB. The mean age of the study cohort was 49 years, 57% were male, 41% were geographically located in the South, and 24% had an Elixhauser index of 4+. Among the 350 patients who did not undergo CLND, 10% experienced recurrence and 22% developed lymphedema. A total of 3367 patients underwent CLND, of which 8% experienced recurrence and 20% developed lymphedema. Completion lymph node dissection did not significantly affect risk of recurrence [odds ratio (OR), 1.370, P = 0.090] or lymphedema (OR, 1.114, P = 0.438). After stratification and propensity score matching, odds of experiencing lymphedema (OR, 1.604, P = 0.058) and recurrence (OR, 1.825, P = 0.058) after CLND were not significantly affected. Rates of CLND had significantly decreased (P < 0.001) overtime, without change in recurrence rate (P = 0.063).

CONCLUSIONS: Electing for nodal observation does not increase the risk of recurrence or reduce risk of lymphedema. Just as CLND does not confer survival benefit, its decreased utilization has not increased recurrence rate.