Surgeon-performed Intraoperative Transoral Ultrasound for Cancer of Unknown Primary

Adult patients suspected of Squamous Cell Carcinoma of Unknown Primary (SCCUP) will be prospectively enrolled at a tertiary head \& neck cancer center at Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark. All patients will undergo Magnetic Resonance Imaging (MRI) and Positron Emission Tomography-Computerized Tomography (PET-CT) prior to examination in general anesthesia. During general anesthesia, Intraoperative Transoral Ultrasound (ITUS) will be performed prior to panendoscopy. Detected tumors will be registered with specified oropharyngeal sub-locations. Blinded to ITUS, a consultant head \& neck surgeon will perform panendoscopy. After examination, the surgeon is unblinded to ultrasound results. Final histopathology results from location-specified biopsies performed will be used as reference standard. The overall detection rate will be compared between ITUS, panendoscopy, PET-CT and MRI with sensitivity and specificity analysis. Oropharynx sub-location specific detection rate of ITUS vs. panendoscopy will be compared with logistic regression analysis.