A Study on How to Safely Guide Surgery for Melanoma and Similar Skin Tumors in Children Using Pathology and Genetic Information

PRIMARY OBJECTIVE: I. To study the feasibility of central risk-based stratification of malignant and atypical cutaneous melanocytic tumors to guide primary surgical management. SECONDARY OBJECTIVES: I. To evaluate the adherence rate to protocol-assigned surgical management in children with newly diagnosed melanoma, atypical Spitz/Spitzoid tumors, and other atypical melanocytic neoplasms. II. To evaluate the surgery-related adverse events profile for patients treated with narrow re-excision without sentinel lymph node biopsy versus wide local excision +/- sentinel lymph node biopsy per standard adult cutaneous melanoma guidelines. III. To describe progression free survival (PFS) and overall survival (OS) in pediatric patients with melanoma, atypical Spitz/Spitzoid tumors, and other atypical melanocytic neoplasms. EXPLORATORY OBJECTIVES: I. To describe surgical reconstruction techniques for pediatric patients with atypical and malignant melanocytic tumors. II. To describe the use of sentinel lymph node biopsy and rate of completion nodal dissection vs observation following positive sentinel lymph node including number of sentinel nodes sampled, size of largest metastatic nodal deposit, location of draining lymph node basin(s), number of lymph nodes resected at completion dissection. III. To describe surgical complications of completion nodal dissection (from time of surgery to 90 days following surgery): wound dehiscence, seroma/hematoma, hemorrhage, infection, skin graft failure, necrosis of flap used for reconstruction, lymphocele, lymphedema, deep vein thrombosis. IV. To evaluate the concordance between local treating center pathologic diagnosis and central pathology review diagnosis. V. To analyze the molecular characterization of melanocytic tumors to identify molecular and immunohistochemical biomarkers correlating with known clinical prognostic factors and outcome. VI. To determine the number of Children's Oncology Group (COG) institutions that open the study within 18 months of activation. OUTLINE: Patients with not atypical pathology are assigned to the Observation Arm. Patients with atypical low-risk tumors are assigned to Treatment Arm A and patients with atypical high-risk tumors are assigned to Treatment Arm B. OBSERVATION ARM: Patients undergo observation throughout the study. TREATMENT ARM A: Patients may undergo narrow margin re-excision without sentinel lymph node biopsy. After completion of study intervention, patients are followed every 6 months for 1 year then every year for up to 5 years. TREATMENT ARM B: Patients undergo wide local excision with or without sentinel lymph node biopsy (SLNB) per standard guidelines. Patients may also undergo blood sample collection, chest x-ray, computed tomography (CT), magnetic resonance imaging (MRI), whole-body fludeoxyglucose F-18 (FDG) positron emission tomography (PET)/CT or PET/MRI, nodal basin ultrasound, and brain MRI on study. After completion of study treatment, patients are followed every 3-6 months for years 1 and 2, every 6 months up to year 5.