[Target volumes in cervical lympadenopathies of unknown primary: toward a selective customized approach? On behalf of...

The treatment of carcinomas of unknown primary revealed by cervical lymphadenopathy is based on neck dissection and nodal and pan-mucosal irradiation to control the neck and avoid the emergence of a metachronous primary. The aim of this review was to assess diagnostic and therapeutic approaches and criteria that may be used for a customized selective approach to avoid severe toxicities of pan-mucosal irradiation. A literature search was performed with the following keywords: cervical lymphadenopathy, unknown primary, upper aerodigestive tract, cancer, radiotherapy, squamous cell carcinoma, variants. The diagnostic workup includes a head and neck scanner or MRI, ((18)F)-FDG PET CT, a panendoscopy and tonsillectomy. Squamous cell carcinoma represents over two thirds of cases. The number of metastatic cervical nodes, nodal level, and histological variant (associated with HPV/EBV status) may determine the primary site origin and might be weighted for the determination of radiation target volumes on a multidisciplinary basis. A selective customized approach is relevant to decrease radiation toxicity only if neck and mucosal control is not impaired. Although no recommendation can yet be made in the absence of sufficient level of evidence, the relevance of systematic pan-mucosal irradiation appears questionable in a number of clinical situations. Accordingly, a customized selective redefinition of target volumes may be discussed and be prospectively evaluated in relation to the therapeutic index obtained.