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.

INTRODUCTION: 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.
MATERIALS AND METHODS: 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.
RESULTS: 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. DISCUSSION: 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.
CONCLUSION: 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.