Sentinel node for malignant melanoma: An observational study of a consecutive single centre experience

Abstract

Introduction: Sentinel node biopsy (SNB) for melanoma gives prognostic information, however the success is dependent on several factors. The aim of this study was to describe outcome data after the introduction of the technique at our centre, including analysis of false negative rate (FNR), predictive factors for positive sentinel node (SN) and non-sentinel node (NSN), as well as prognostic factors for melanoma-specific survival (MSS).

Materials and methods: This is a retrospective observational study of a prospectively kept database at Sahlgrenska University Hospital. Between March 2000 and December 2013, 769 consecutive patients with cutaneous malignant melanoma undergoing SNB were included. The median follow-up time was 55 months (2-179 months). Tumour load in the SN was categorized according to the largest tumour deposit, low when ≤1 mm and high when >1 mm.

Results: The FNR was 20% and the SN positivity rate was 14% with a decrease in both FNR and SN positivity rate during the study period. In multivariate analysis the only predictive factor for a positive SN was Breslow thickness. The 5-year melanoma specific survival (MSS) was 81% and in multivariate analysis the prognostic factors were SN-status (low metastatic load HR = 2.6, p = 0.001; high metastatic load HR = 2.7, p = 0.004) followed by Breslow thickness and ulceration.

Conclusions: In this study Breslow thickness was the only independent predictive factor for a positive SN, no predictive factors were identified for NSN. Independent prognostic factors for MSS were SN status, Breslow thickness and ulceration. Interestingly, there was no survival difference depending on SN tumour burden when using 1 mm as cut-off.

Keywords: Melanoma; Sentinel node.