Sentinel Lymph Node Biopsy in Cutaneous Melanoma: Results of a Single-Center Analysis

Sentinel lymph node biopsy (SLNB) in cutaneous melanoma is a staging step in cases of unaffected regional lymph nodes. This method is included in routine practice in many medical facilities of the Russian Federation. Aim. To analyze the results of SLNB in cutaneous melanoma performed using gamma scintigraphy technique with the 99mTc-containing technefit radiopharmaceutical agent. Materials and methods. The prospective study included 97 patients (39.2 % (38/97) men and 60.8 % (59/97) women) with primary cutaneous melanoma who received surgical treatment at the Republican Clinical Oncological Dispensary (Ufa) between February of 2021 and January of 2023. Mean patient age was 57.2 ± 13.2 years (95 % confidence interval (CI) 53.8–61.3 years), mean Breslow thickness per biopsy and histological examination after wide tumor resection was 2.89 ± 2.7 mm (95 % CI 2.2–3.76 mm), median follow-up period was 14 months (interquartile range 8–18 months). 99mTc-containing technefit radiopharmaceutical agent was administered intradermally around melanoma/scar. Accumulation of the radiopharmaceutical in the regional lymph nodes was evaluated using single-photon emission computed tomography/computed tomography (SPECT/CT). Intraoperatively the sentinel lymph node (SLN) was identified using a portable gamma probe. Morphological evaluation was performed in accordance with the protocol approved at the Republican Clinical Oncological Dispensary and based on the updated protocol of the European Organisation for Research and Treatment of Cancer (EORTС) (2019). Results. The percentage of successfully mapped SLNs after radiopharmaceutical administration was 93.8 % (91/97). Mean number of visualized SLNs per SPECT/CT data was 1.7 ± 1.1 SLN (95 % CI 1.5–1.9). SLN biopsy was performed in 91.8 % (89/97) patients. Mean number of identified SLNs during SLNB was 1.9 ± 1.2 (95 % CI 1.6–2.3). Histological and immunohistochemical examinations showed SLN metastases in 22.5 % (20/89) patients; in 77.5 % (69/89) patients, no lymph node metastases were found. SLN biopsy allowed to perform disease staging. During follow-up in 3 patients with negative SLNs metastases in the regional lymph nodes were found, as well as in 2 patients with positive SLNs. The frequency of false negative SLNB results was 13 % (3/23), negative post-test probability was 2.8 % (2/69). V600E mutation in the BRAF gene was found in 42.3 % (22/52) patients. Conclusion. SLN biopsy using the technefit radiopharmaceutical showed satisfactory results: SLNs were identified in 93.8 % of cases. Morphological examination showed SLN metastases in 22.5 % (20/89) of patients.