Clinical Decision Making in Melanoma: How to Treat in 2024?

Age specific incidence rates (ASIR) continue to rise globally, the highest being in Australia (47/100,000). However, the biggest expected annual percentage change has been in East Asia, where the ASIR has increased to about 0.5 per 100,000.
Most melanoma arises de novo ie not on pre-existing naevi and new, changing or symptomatic melanocytic lesions should be considered for biopsy depending on clinical morphology and dermatoscopic features. In Asians, most melanoma occurs on acral sites, including the nail unit.
Diagnostic biopsies should aim to remove all of the primary lesion but large or equivocal lesions can be subjected to incisional biopsy without risk of spreading tumour cells.
Staging features on histology are the Breslow thickness and ulceration. The Primary Tumour (T) is graded pT1-4 accordingly and re-excision is performed with clinical margins determined by the thickness. In tumours graded > pT1b, a sentinel node biopsy should be considered before re-excision, mainly as a staging tool (N0-3) and with respect to adjuvant or other chemotherapy. 
Staging (0-IV) is performed using AJCC 8th ed criteria, with reference to the primary tumour (T0-4) and also to nodal (N0-3) or metastatic involvement (M0-3).
Further investigations depend mainly on symptoms and staging, as does follow up