PubMed:: "Nasopharyngeal Neoplasms"[Mesh] OR (nasopharyn*[tiab] AND cancer[sb]);; Embase.com:: 'nasopharynx tumor'/de OR 'nasopharynx cancer'/exp OR (nasopharyn*:ab,ti AND (carcinoma*:ab,ti OR tumor*:ab,ti OR tumour*:ab,ti OR neoplasm*:ab,ti OR cancer*:ab,ti OR squamous:ab,ti));; Cochrane Library:: (nasopharyn*):ti,ab,kw AND (carcinoma* OR tumor* OR tumour* OR neoplasm* OR cancer* OR squamous):ti,ab,kw
