title: Synchronous and metachronous tumours in patients with head and neck cancer.
mesh_terms: D002294:Carcinoma, Squamous Cell; D006258:Head and Neck Neoplasms / Q000556:secondary; D006801:Humans; D008175:Lung Neoplasms / Q000556:secondary; D009378:Neoplasms, Multiple Primary; D011446:Prospective Studies; D012189:Retrospective Studies