Comprehensive management of HPV-related squamous cell carcinoma of the head and neck of unknown primary.

Abstract

Human papillomavirus (HPV)-related squamous cell carcinoma of unknown primary (SCCUP) is currently rising in incidence but lacks a validated management approach. This paper reviews the clinical presentation, diagnosis, and treatment of HPV-related SCCUP. The Medline/Pubmed database was searched by using the following keywords "CUP", "cancer of unknown primary", "HPV", "human papilloma virus", and "head and neck". The references of the publications of interest were also screened for relevant papers. The clinical assessment of HPV-related SCCUP includes a complete clinical examination, an endoscopic evaluation with white-light and narrow band imaging, and radiologic assessment using morphologic and metabolic imaging. If the diagnosis remains unconfirmed, endoscopic examination under anesthesia with tonsillectomy ± base of tongue mucosectomy is performed. The therapeutic rationale aims to eradicate the involved lymph nodes and potential primary tumor with a sequence of chemoradiotherapy and neck dissection. As a general approach, p16-negative SCCUP are truly HPV negative, whereas p16-positive specimens require confirmation with HPV in situ hybridization or polymerase chain reaction to confirm HPV infection. If a cervical metastasis is considered HPV positive, the primary lesion is likely in the oropharynx, and further diagnostic interventions such as tonsillectomy seems to be mandatory. Whether the optimal treatment is neck dissection followed by adjuvant radiotherapy or concomitant chemoradiotherapy (CRT) (in case of extranodal extension or advanced lymph node stages) or definitive CRT followed by neck dissection (in case of positive 18 F-FDG-PET/CT) remains a matter of debate. Solid scientific evidence supporting treatment de-escalation in HPV-related SCCUP is lacking, and the results of ongoing trials are at the brink of reporting. Currently, the treatment of patients with HPV-related SCCUP should not differ from the standard treatment of other SCCUP patients and is similarly based on the staging of the disease and general condition of the patient.