The radiological unknown primary of the head and neck: Recommendations for imaging strategies based on a systematic review

Abstract

Objectives: To develop recommendations for the radiological investigation of clinically occult primary cancer in the head and neck. Design and Setting: In accordance with PRISMA guidelines, a search was performed on Medline, Embase and Cochrane library databases to investigate the efficacy of ultrasound guided Fine Needle Aspiration (US FNAC), contrast enhanced CT (CECT), magnetic resonance imaging (MRI) and 18F-fluorodeoxyglucose PET-CT (18F-FDG PET-CT) in the investigation of head and neck squamous cell carcinoma from an unknown primary (HNSCCUP) presenting with a metastatic cervical lymph node (s). The Quality Assessment of Diagnostic Accuracy Studies Version 2 tool and SIGN 50 guidelines were used to assess the risk of bias and quality of the included studies. Participants: Adult patients presenting with metastatic cervical lymph nodes from a HNSCCUP. Main Outcome measures: Utility of different imaging modalities (PET-CT, MRI, CE CT and US FNAC in the management of HNSCCUP). Results: Twenty-eight studies met inclusion criteria; these were meta-analyses, systematic reviews, prospective and retrospective studies. Conclusions: The optimal imaging strategy involves utilisation of various imaging modalities. US FNAC can provide the initial diagnosis and HPV status of the occult primary tumour. CECT and MRI detect up to 44% of occult tumours and guide management. FDG PET-CT is the most sensitive imaging modality for the detection of CUP and should be performed prior to panendoscopy.