A negative sentinel node in melanoma patients; no need to worry?

Background: Since its introduction, the outcome of the SLNB is one of the most important prognostic factors in melanoma patients. A negative sentinel node however, does not guarantee a recurrence-free follow-up. This study was performed to determine risk factors of regional or systemic disease recurrence in node negative melanoma patients. Material and methods: Data concerning patients treated between 1996 and 2014 in the University Medical Center Groningen were prospectively collected. The database contained patient and tumor characteristics, follow-up, recurrence and survival data. Cox regression analyses were used to determine variables associated with systemic first site of recurrence in sentinel node negative patients. Results: A total of 668 SLNB's were performed between 1996 and 2014. The SLNB was positive in 27.8% of the patients and negative in 68.6% of the patients. Recurrence rates were 53.2% in the SLNB positive group and 17.9% in the SLNB negative group. Thirty and a half percent of all patients recurred (204/668), 77% of these patients progressed to stage IV during the course of their disease. Multivariate cox regression analysis of factors associated with immediate stage IV recurrence in sentinel node negative patients revealed melanoma located on the head/neck (HR 3.09, p: 0.035) and the presence of ulceration (HR 2.31, p: 0.035) as significant factors. In sentinel node negative patients with a nodular melanoma the ever recurrence rate was 38/128 (29.7%), if ulceration was present the recurrence rate was 43.1%, the first site of recurrence was systemic in 64% of these patients. Analysis of ever stage IV recurrence in all patients revealed SLNB positive results of strong predictive value (HR 3.00, P: