Re-evaluation of a Scoring System to Predict Nonsentinel-Node Metastasis and Prognosis in Melanoma Patients

Abstract

We previously developed a scoring system based on patient age and total sentinel node (SN) tumor size to predict nonsentinel node (NSN) metastasis. The score relied on the cutoff values of 55 years for age and 5 mm total SN tumor size to stratify SN-positive patients into 3 categories. Its validity, however, remains in doubt given that it was developed by retrospective review of a single, relatively small cohort of SN-positive melanoma patients. The purpose of this study was to validate this scoring system and to determine its value in predicting patient survival. A review of melanoma patients who had undergone sentinel node biopsy and completion lymph node dissection (CLND) at the Melanoma Institute Australia from June 1992 until April 2009 was undertaken. The significance of the correlation of each of the score variables (age and total SN tumor size) with NSN metastasis, melanoma-specific survival, and overall survival was tested. Cox logistic regression analysis was used to determine the degree of correlation of the score system to each of the 3 outcomes. Six hundred six SN-positive patients were identified and included in this study. The score system did not significantly correlate with NSN metastasis (p = 0.1049). However, it did significantly correlate with both overall survival (p < 0.0001) and disease-specific survival (p = 0.0014). Our results revealed that the previously developed scoring system does not predict NSN metastasis; however, it was found to be a powerful predictive tool for overall and disease-free survival in SN-positive melanoma patients.