Setting the stage: Contemporary staging of non-melanomatous skin cancer and implementation of the new American Joint Committee on cancer eighth edition staging manual

Non-melanomatous skin cancer (NMSC) generally refers to basal cell and squamous cell carcinoma of the skin. The majority of patients are curatively treated with simple excision. Only few present with locally advanced disease or have evidence of high-risk features, placing them at an elevated risk of relapse. In such cases, further investigations may guide the multidisciplinary management plan. There are no universally agreed on indications for recommending additional staging investigations, due to a lack of prospective data reporting their impact on patient outcomes. Some generally agreed upon indications are discussed in this review article. Most commonly, computed tomography (CT) and magnetic resonance imaging (MR) are used in cases of locally advanced NMSC for staging purposes and surgical planning. While Positron Emission Tomography (PET)/CT and sentinel lymph node biopsy have shown utility, data is lacking to establish their roles in the staging algorithm. An updated NMSC system was included in The American Joint Committee for Cancer eighth edition staging manual (AJCC8). Under AJCC8 the majority of patients with regional disease are upstaged by the presence of extranodal extension, however, this updated system appears to provide limited prognostic discrimination between the nodal categories and the overall TNM stages. This review article will explore the contemporary role of staging investigations, including evolving technologies, and review the changes implemented in AJCC8. It will also discuss the implications of the AJCC8 decision to assign patients with p16-positive cervical nodal SCC with an unknown primary to the oropharyngeal staging system, with particular relevance to clinicians working in areas of high NMSC incidence.