Unknown primary cancer of the head and neck: a multidisciplinary approach

The management of patients with cervical lymph node metastases from an unknown primary cancer (CUP) remains a matter of controversy. Although new advanced diagnostic tools, such as positron emission tomography, have recently been introduced in oncology, the frequency of this tumour entity in clinical practice means it is still relevant. Recently introduced molecular profiling platforms may provide biological classification for the primary tissue of origin as well as insights into the pathophysiology of this clinical entity, including the characterisation of the Epstein-Barr virus and human papilloma virus genomas in the metastatic cervical nodes. Due to the lack of randomised trials, a standard therapy has not been identified yet. Although neck dissection followed by post-operative radiotherapy is the most generally accepted approach, there are other curative options that can be used in some patients: neck dissection alone, nodal excision followed by post-operative radiotherapy or radiotherapy alone. A major controversy remains in the target radiation volumes that range from ipsilateral neck irradiation to prophylactic irradiation of all potential mucosal sites and both sides of the neck. Finally, the administration of concurrent chemotherapy is currently being advised for patients with adverse prognostic factors.