Features Predicting Sentinel Lymph Node Positivity in Merkel Cell Carcinoma

Abstract

A B S T R A C T PurposeMerkel cell carcinoma (MCC) is a relatively rare, potentially aggressive cutaneous malignancy. We examined the clinical and histologic features of primary MCC that may correlate with the probability of a positive sentinel lymph node (SLN). MethodsNinety-five patients with MCC who underwent SLN biopsy at the University of Michigan were identified. SLN biopsy was performed on 97 primary tumors, and an SLN was identified in 93 instances. These were reviewed for clinical and histologic features and associated SLN positivity. Univariate associations between these characteristics and a positive SLN were tested for by using either the 2 or the Fisher's exact test. A backward elimination algorithm was used to help create a best multiple variable model to explain a positive SLN. ResultsSLN positivity was significantly associated with the clinical size of the lesion, greatest horizontal histologic dimension, tumor thickness, mitotic rate, and histologic growth pattern. Two competing multivariate models were generated to predict a positive SLN. The histologic growth pattern was present in both models and combined with either tumor thickness or mitotic rate. ConclusionIncreasing clinical size, increasing tumor thickness, increasing mitotic rate, and infiltrative tumor growth pattern were significantly associated with a greater likelihood of a positive SLN. By using the growth pattern and tumor thickness model, no subgroup of patients was predicted to have a lower than 15% to 20% likelihood of a positive SLN. This suggests that all patients presenting with MCC without clinical evidence of regional lymph node disease should be considered for SLN biopsy.

Merkel cell carcinoma: An Australian perspective and the importance of addressing the regional lymph nodes in clinically node-negative patients

“…Indeed in a large study of 95 patients undergoing SLNB from the University of Michigan the authors concluded that after considering variables such as tumor thickness, size, mitotic rate, and growth pattern there was no favorable subgroup that had a lower than 15% to 20% risk of having a positive SLNB result. 35 In patients who have a positive SLNB result, the risk of further metastatic disease in the remaining lymph nodes is not known, nor is the most appropriate form of treatment. Gupta et al 33 found that in patients with a positive SLNB result, those who did not proceed to treatment of the lymph node basin had a significantly worse DFS than those who received nodal treatment.…”

Five Hundred Patients With Merkel Cell Carcinoma Evaluated at a Single Institution

“…26,27 Sentinel lymph node biopsy (SLNB) has been described in clinically node-negative MCC in an attempt to more accurately stage patients and guide subsequent treatment recommendations. 14,21,28,29 Regional nodal treatment of either micro-or macroscopically involved LN includes lymph node dissection (LND) with or without adjuvant nodal RT or the use of therapeutic nodal RT alone (no surgery).…”

Controversies in Sentinel Lymph Node Biopsy for Ocular Neoplasms

“…The rate of sentinel lymph node positivity correlates highly with increasing diameter, increasing thickness, and increasing mitotic rate of the lesion. 19 In a retrospective chart review of 15 patients with Merkel cell located anywhere on the body, it was determined that the most important predictor of survival was the status of lymph node metastasis. Furthermore, lymph node metastasis was the first sign of recurrence in 60% of cases.…”