Detection and Oncologic Outcomes of Head and Neck Squamous Cell Carcinoma of Unknown Primary Origin

Background/aim To assess factors that predict detection of tumors and oncologic outcomes in head and neck squamous cell carcinoma of unknown primary (SCCUP). Patients and methods This was a retrospective cohort study at a single tertiary care institution. Results The primary site was detected at examination under anesthesia (EUA) in 92 (51.1%) patients. The primary site was detected by directed biopsies in 60 (65%), palatine tonsillectomy in 28 (30.4%), and lingual tonsillectomy in 4 patients (4.3%). Four of eight lingual tonsillectomies were positive (50%). Primary locations included: palatine tonsils (51, 28.3%), base of tongue (37, 20.6%), larynx (4, 2.2%), oral cavity (3, 1.67%) and nasopharynx (1, 0.6%). Human papillomavirus (HPV) positive status (HR=0.26, p=0.004) and treatment with chemoradiation (CRT) (HR=0.38, p=0.004) were associated with better disease free survival (DFS). Conclusion A primary site was located after aggressive investigation in approximately half of the patients. More research is warranted towards the use of lingual tonsillectomy. Predictors of favorable prognosis included HPV positive status and treatment with CRT.