Surgical N-staging in patients with primary melanoma of the skin of the trunk and extremities using fluorescent technologies

Introduction. Cutaneous melanoma remains a significant problem in modern oncology in Russia and many countries worldwide. According to the global cancer registry data for 2022, 331,722 new cases of skin melanoma were recorded, of which 3,9 % were patients from the Russian Federation. Objective. To evaluate the diagnostic value and safety of sentinel lymph node biopsy (SLNB) using indocyanine green (ICG) fluorescence mapping in patients with clinically localized stages of trunk and extremity melanoma. Materials and methods. A single-center prospective study included 62 patients with clinically localized stages of trunk and extremity melanoma (cT1-4N0M0, ECOG 0-1) who underwent wide excision of the skin tumor with sentinel lymph node biopsy (SLNB) using ICG fluorescence mapping. To exclude loco-regional recurrence and other types of progression after radical surgery, patients underwent follow-up examinations every 3–6 months depending on the disease stage. Results. Lymph nodes were identified in all 62 patients (100 %). This method demonstrated high diagnostic value: sensitivity – 100% and specificity – 100 %. Immunohistochemical (IHC) examination revealed the presence of metastases in sentinel lymph nodes in 9 (14,5 %) patients, and their absence in 53 (85,5 %) patients (pN0). Notably, follow-up examinations of patients with no metastatic lymph node involvement pN0 ("SLNB-") showed no signs of loco-regional recurrence. During follow-up examinations at 6 months, loco-regional recurrences were detected in 2 (3,2 %) patients, and distant metastases were detected in 1 (1,6 %) patient 18 months after surgery; all these patients had pN1 ("SLNB+"). In a subset of patients with histologically negative results, extended pathological examination (ultrastaging) was performed, which revealed additional micrometastases in only 2 (3,2 %) patients. This finding did not change the clinical stage and showed no correlation with recurrences during the follow-up period. Conclusion. Thus, in clinically localized stages of trunk and extremity melanoma, SLNB with ICG fluorescence mapping is not only safe but also represents a highly effective diagnostic method that enables timely and accurate staging of cutaneous melanoma with personalized treatment selection and further oncological follow-up. This approach ensures high precision of surgical intervention and minimization of its extent on regional lymph collectors.