Transoral robotic surgery for the benefit of patients with head and neck cancer of unknown primary: our experience at St George's University Hospital, London.

Head and neck carcinoma of unknown primary represents 1-5% of all head and neck cancers and presents a diagnostic and therapeutic dilemma. In approximately 40% of cases, a primary tumour location remains unknown despite investigation. With advancements in our understanding of the role of high-risk human papilloma virus in head and neck cancer, transoral robotic surgery presents an option for diagnosis and therapy. This is a retrospective case series from a single centre. Case notes were reviewed for 28 patients who had transoral robotic surgery for head and neck carcinoma of unknown primary between May 2015 and July 2019. Transoral robotic surgery identified an oropharyngeal primary tumour in 19 of 28 (67.8%) patients. All oropharyngeal primaries were p16 positive. The base of tongue identification rate was 63.2%. Median length of inpatient stay postoperatively was 1.0 day. Normal oral intake resumed within 48 hours in 96% (27/28) of patients. Three patients (10.3%) suffered minor postoperative bleeds that were all managed conservatively. The base of tongue primary identification rate (63.2%) in this series is consistent with that previously reported (43-63%; 95% confidence interval). Primary tumour identification rate if a patient is p16 positive is 86.3% (19/22), with 100% of these being oropharyngeal. We suggest future investigation into p16 status as a means of stratifying patients with head and neck carcinoma of unknown primary for transoral robotic surgery. Transoral robotic base of tongue mucosectomy (or lingual tonsillectomy) is a promising technique that offers a high yield of positive identification for the primary tumour. It is well tolerated with minimal associated morbidity. Our findings are comparable with those in the current literature.