LAUSR

Accurate staging of a skin cancer is essential in order to properly plan its management. Staging takes account of the tumour itself (T), whether it has spread to lymph glands (nodes – N) and whether it has spread to distant organs (metastases – M). The TNM classification system is constantly being revised in the light of new research. The latest edition for skin cancer (TNM8) was published in 2016 by the Union for International Cancer Control, and has now been adopted by the relevant bodies in the U.K. TNM8 displays significant changes from TNM7 in the staging of skin cancers including the commoner basal cell carcinoma and squamous cell carcinoma (non‐melanoma skin cancers ‐ NMSC), melanoma, as well as rarer skin tumours. These changes impose additional responsibilities on the clinicians seeing the patient. These include measuring the maximum diameter of every potential NMSC and writing this on the form to accompany the excised tumour to the laboratory. In addition, the form must state whether it is possible to manually feel enlarged glands or visualise them on a scan. Patients with thin melanomas less than 0.8mm whose lymph nodes have been shown to be free of cancer by a technique known as sentinel lymph node biopsy now have a lower TNM stage. Their hospital follow‐up is reduced from 5 years to 1 year which is an important advance. Some microscopic features previously thought to indicate the aggressiveness of a tumour, have been dropped from the TNM8 classification. For example the differentiation (deviation from normal tissue appearance) of a squamous carcinoma and the number of visibly dividing cells in a melanoma are no longer considered important.