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

Merkelcell.org Summary

Patients who are diagnosed with Merkel cell carcinoma often receive sentinel lymph node biopsies (SLNB; learn more at Sentinel Lymph Node Biopsy – NCI). Sentinel lymph nodes (SLNs) are the first lymph nodes where cancer is most likely to spread. A sentinel lymph node biopsy (SLNB) is a procedure where these lymph nodes are removed and checked for cancer that can’t be seen on scans or felt during an exam. Accurate SLNB results help doctors understand how far MCC has spread and choose the best treatment, which can lower the chance of the MCC coming back. However, for some patients, the SLNB results may be unclear, or the procedure may not be medically safe for them.

This study included 696 MCC patients. About 75% of them had a SLNB, and 35% of those patients had a positive SLNB result. Patients were followed for an average of 3 years after the procedure. The study found that patients who received an SLNB lived longer and went longer without their MCC coming back on average compared to patients who did not receive a SLNB at all. Among those who did have the procedure, patients with a negative SLNB result had better survival and stayed MCC-free longer than those with a positive result.

Authors suggest that people who had SLNB may have a better outcome, because the procedure helps doctors find tiny amounts of cancer that may have already spread to the lymph nodes. When this hidden spread is detected early, patients can receive the right follow-up treatment—such as targeted radiation—which can prevent MCC from coming back. In contrast, people who skipped the SLNB were often older or had other health issues, and their cancer was more likely to return in nearby lymph nodes because this early spread went unnoticed and untreated.

This study adds to the strong evidence that SLNBs should be done for MCC patients whenever it is safe to do so. SLNB results help doctors find out if the MCC has spread and allow them to choose the most accurate and effective treatment plan.

Abstract

Background

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.

Methods

A retrospective review included patients from 1999 to 2024 with clinical N0, resectable MCC.

Results

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.

Conclusions

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.