Recurrence after sentinel lymph node biopsy in cutaneous melanoma: a single-center experience in Slovak patients

The standard approach in the management of cutaneous malignant melanoma is considered to be a complete excision of the primary lesion with an appropriate margin of the normal tissue according to Breslow thickness. Usually sentinel lymph node biopsy (SLNB) can help to determine the nodal status, and thus improve the accuracy of staging of the disease. However, the role of SLNB in melanoma treatment remains controversial. NCCN guidelines strongly support routine performance of therapeutic lymphadenectomy in all melanoma patients with clinically positive nodes without radiographic evidence of distant metastases. Patients with positive SLNB should have had completion lymph node dissection (CLND) for regional disease control. Between 2012 and 2016, 168 consecutive patients underwent surgery for primary cutaneous malignant melanoma at St. Elisabeth Cancer Institute in Bratislava. The indication for SLNB and the procedure was made according to international guidelines. In this retrospective study, a cohort of 78 patients was analyzed (35 women and 43 men). Inclusion criteria comprised patients with cutaneous melanoma with no evidence of distant metastases or clinical lymphadenopathy. SLNB comprised a dual labelling method (Tc-99m Nanocolloid / blue dye) in a one-day protocol. Median follow-up was 657 days. The primary composite outcome was the time to the first disease-related event (death, reintervention, worsening of symptoms). Primary outcome measures were overall (disease-specific) and disease-free survival. The overall identification rate of SLN in melanoma patients by dual labelling method was 98.5%. All patients with positive SLNB on frozen section underwent complete regional lymphadenectomy. Using multivariable analysis Breslow thickness of the lesion (p=0.00004, HR 4.03 on logarithmic scale) was identified as the strongest independent predictor of the disease-free survival (DFS) and male gender was significant predictor of DFS. An increase in tumor thickness was associated with significantly higher risk of an event. Neither SLN positivity nor initial S-100 level proved to be significant predictors of the event at the 0.05 level of probability. Multidisciplinary approach represents the gold standard of care for melanoma patients and surgery remains the best option for most localized cases. Although the usefulness of SLNB procedure has been questioned, it provides an excellent staging method, moreover, it can identify high-risk patients. The routine use of completion lymphadenectomy after a positive SLNB is still controversial. It is not clear whether CLND following a positive SLN biopsy improves survival but it could provide regional disease control.