Clinical and Treatment Approach of Multiple Head and Neck Cancers.

The development of a second primary malignancy in patients with head and neck cancer (HNC) is not a rare event. According to the literature, the incidence of multiple HNCs is increasing in recent years due to improved diagnostic tests, meliorated screening and surveillance of patients with cancer, more sophisticated treatment, increased life expectancy and high population survival. The risk of developing second primary cancer increases by 3% per year in patients who have survived HNC. Second tumors can be diagnosed either simultaneously (synchronous) or more than six months after the index tumour (metachronous). Nowadays, the situation of patients with multiple primaries HNCs is of increasing relevance and importance and follow-up of those patients is recommended, not only to detect relapse and manage treatment-related toxicities but also for early detection of metachronous HNCs. This review focuses on practical clinical implications of the management of patients with multiple HNCs. Diagnostic challenges and distinction from recurrence, treatment planning and surveillance, prognostic implications and risk stratification, precision oncology and future directions are the main topics contained in it confirming the necessity of a highly customized and interdisciplinary clinical and treatment approach for the management of HNCs, both synchronous and metachronous.