Association between mitotic rate and lymph node metastasis in thin melanoma in the general population..

e20039 Background: Mitotic rate was incorporated into the AJCC 7th edition staging system for cutaneous melanoma because of its prognostic impact on melanoma-specific survival in patients with thin melanomas (≤ 1mm). However, the role of mitotic rate in the prediction of sentinel lymph node (SLN) involvement is still controversial. The purpose of this study is to quantify the association between mitotic rate and lymph node (LN) metastasis in thin melanoma in a population-based registry. Methods: The SEER database was queried for patients with thin melanoma diagnosed in 2010 who had WLE and LN surgery with known clinical and pathologic information for their primary lesions, including mitotic rate. Patients were divided into 3 subgroups based on mitotic rate (0, 1-2, >2). Multivariate logistic regression analyses were performed to identify factors predictive of LN metastasis. Results: A total of 524 thin melanoma patients who had WLE and LN surgery were included in the final cohort, 46 (8.8%) of whom had po...