New staging system for metastatic skin cancer of the head and neck

An international group, including three Australian centres, has proposed a new staging system which appears to more accurately predict the prognosis and response to treatment of patients with metastatic skin cancer arising in the head and neck region.The authors discussed the relatively frequent occurrence of cutaneous squamous cell carcinoma (SCC) of the head and neck in Australia, especially in elderly Caucasian men. It spreads to lymph nodes in the parotid gland and neck in about 5% of cases. The current TNM system classifies patients as N0 or N1, but such a simple system does not discriminate well. The authors had developed a more detailed system and trialled it in previous studies. The new scheme separated parotid and other cervical lymph nodes. Parotid metastases were classified as P0, P1 (≤ 3 cm), P2 (3 to 6 cm) or P3 (> 6 cm or involving the facial nerve or skull base). Other neck nodes were N0, N1 (single ipsilateral node ≤ 3cm) or N2 (single node > 3 cm or multiple or contralateral nodes).This retrospective multicentre study, to test the new staging system, involved 322 patients with metastatic cutaneous SCC of the parotid gland and/or neck. Patients were recruited from three Australian (245 patients) and three North American (77 patients) centres. They were treated for cure and had a minimum follow up of two years. Two hundred and ninety one patients were treated surgically and 267 received radiotherapy.The parotid region alone was clinically involved in 217 (149 P1, 78 P2, 33 P3) and the neck alone in 62 patients (26 N1, 36 N2). Both regions were involved in 43 patients. The neck nodes were pathologically involved in 32% of patients with parotid metastases. The five-year disease-specific survival was 74%. Recurrent disease occurred in 105 patients (33%) and involved the parotid in 42, the neck in 33, and distant sites in 30 patients. Parotid recurrence did not vary significantly with P stage but survival was 69% in patients with advanced P stage and 82% in those with early P stage (p = 0.02). Clinical neck involvement in patients with parotid metastases did not significantly worsen survival but pathological involvement decreased survival from 79 to 61% (p = 0.027). Multivariate analysis showed that clinical P3 parotid stage (p = 0.033) and pathologic N1or N2 neck stage (p = 0.005) were significant predictors of disease free survival.The authors concluded that the results supported the separation of parotid and neck disease in a new staging system but the value of the nodal subgroups was uncertain and required further study. Reference...