Sentinel lymph node biopsy is associated with improved survival in Merkel cell carcinoma

Abstract

Background: Although sentinel lymph node biopsy (SNB) has become a standard for Merkel cell carcinoma (MCC), the impact on survival is unclear. To better define the staging and therapeutic value of SNB, we compared SNB with nodal observation.

Methods: Patients with clinical stage I and II MCC in the Surveillance, Epidemiology, and End Results (SEER) registry undergoing surgery between 2003 and 2009 were identified and divided into two groups-SNB and observation.

Results: A total of 1,193 patients met the inclusion criteria (SNB 474 and Observation 719). The median age was 78 years, and the majority were White (95.3 %), male (58.8 %), received radiation therapy (52.9 %) and had T1 tumors (65.3 %). Twenty-four percent had a positive SNB. SNB patients were younger (73 vs. 81 years; p < 0.0001), had T1 tumors (69.6 vs. 62.5 %; p = 0.04) and received radiotherapy (57.8 vs. 40 %; p < 0.0001). Among biopsy patients, a negative SNB was associated with improved 5-year MCC-specific survival (84.5 vs. 64.6 %; p < 0.0001). Univariate analysis demonstrated an increased 5-year MCC-specific survival for the SNB group versus the Observation group (79.2 vs. 73.8 %; p = 0.004), female gender (83.2 vs. 70.4 %; p = 0.0004), and lower T stage (p < 0.0001). On Cox regression, diminished survival was noted for the Observation group (risk ratio [RR] 1.43; p = 0.04), male gender (RR 2.06; p < 0.0001), and a higher T stage.

Conclusion: SNB for MCC provides prognostic information and is associated with a significant survival advantage.