Sentinel Lymph Node Biopsy in Patients With Thick Primary Cutaneous Melanoma

The clinical value of sentinel lymph node biopsy (SLNB) in patients with thick melanoma is uncertain. The purpose of this study was to investigate the correlations between survival and lymph node status in thick melanomas.

Of a total of 736 melanoma patients registered between 2000 and 2016, 50 presented with thick melanomas (≥ 4.0 mm) without distant metastatic disease. All patients were examined with a whole-body magnetic resonance imaging, or computed tomography, and positron emission tomography-computed tomography depending on the incorporation of the new technology in our medical institutions. They were studied according to the following procedure: 1) preoperative determination of regional lymph node along with the estimation and localization of sentinel lymph node (SLN) (dynamic isotope lymphography); 2) intraoperative localization and SLNB (lymphatic mapping); and 3) histopathology. Patient and tumor features were collected.

Mean follow-up was 40 months, and 37% had a follow-up ≥ 5 years. A positive SLN was identified in 28 patients (56%). No significant difference in melanoma-specific overall survival was observed in terms of the primary tumor site. Hazard ratios (HRs) were statistically significant for SLNB-positive group and mitotic rate (MR) > 3 mm², but not for presence of ulceration. Mortality risk in the SLN-positive group was almost fourfold greater than that in the SLN-negative group at any time of follow-up.

SLN status, along with MR, can provide valuable prognostic information in patients with thick primary cutaneous melanoma.