Recurrence and Survival Outcomes in Patients with Primary Merkel Cell Carcinoma with Positive, Negative, or Not Performed Sentinel Lymph Node Biopsy.

Abstract

Merkel cell carcinoma (MCC) is a rare, aggressive cutaneous malignancy. Sentinel lymph node biopsy (SLNB) might be omitted for various reasons, such as comorbidities. This study evaluates the recurrence and survival in MCC for patients with different SLNB status. A retrospective review included patients from 1999 to 2024 with clinical N0, resectable MCC. A total of 696 patients were identified (median age 76 years; 68% male). Sentinel lymph node biopsy was performed in 75%, and 35% of patients had a positive SLNB. Reasons for omission of SLNB included comorbidities (34%), patient choice (31%), lack of lymphoscintigraphy drainage (18%), and other/unknown (17%). Patients who omitted SLNB were older (79 vs. 75 years, P < .001) and more likely to experience recurrence (58% vs. 30%, P < .001). Median follow-up was 3 years. Median recurrence-free survival (RFS) (4.2 years vs. 8.8 months, P < .0001), disease-specific survival (DSS) (not reached for either, P < .0001), and overall survival (OS) (6.8 vs. 3.6 years, P < .0001) were longer for patients who underwent SLNB. On multivariable analysis, RFS (HR 2.0, P < .001), DSS (HR 1.7, P = .01), and OS (HR 1.3, P = .04) remained longer for patients who underwent SLNB. Patients with MCC who omitted SLNB had significantly worse RFS, DSS, and OS than those who underwent SLNB. This study supports the role of SLNB for MCC whenever feasible, with great utility in staging and a positive trend on recurrence and survival.