Sentinel lymph node biopsy in patients with thin melanomas.

The aim of the present study is to report our experience with lymphatic mapping (LM) and sentinel lymph node biopsy (SLNB) in a selected group of patients with thin primary cutaneous melanomas. Fifty patients (22 females and 28 males; mean age, 57.8 years; range, 30-77 years) with a mean tumor thickness of 0.63 mm (range, 0.24-1.00 mm) underwent LM/SLNB. Twenty-eight (56%) of them had Clark level II, 20 (40%) had Clark level III, and two (4%) had Clark level IV. Tumor ulceration was present in two patients (4%) and histological regression in 35 patients (70%). Sentinel lymph node (SLN) metastases occurred in two of 50 patients (4%). The first case was a 0.88-mm thick, Clark level III, non-ulcerated superficial spreading melanoma of the trunk, without any regression. The second case was a 0.95-mm thick, Clark level IV, non-ulcerated superficial spreading melanoma of the neck, with regression. Both patients were disease-free 76 and 50 months after the SLNB procedure and followed complete lymph node dissection, respectively. The patients with negative SLN were disease-free after a median follow up of 44 months (mean, 43.2; range, 15-84 months). Published data and our experience suggest that LM/SLNB is not routinely indicated for melanomas less than 0.75 mm. Our results confirmed the accuracy of the new American Joint Committee on Cancer/International Union Against Cancer criteria, in which SLNB is required for thin melanomas less than 1.0 mm when they have ulceration or Clark level IV and V invasion.