A systematic review on Transoral Robotic Surgery (TORS) for Carcinoma of Unknown Primary origin: Has Tongue Base Mucosectomy Become Indispensable?

BACKGROUND: Transoral robotic surgery (TORS) is increasingly used in head and neck surgery and in carcinoma of unknown primary (CUP) origin specifically. Due to the rising incidence of human papilloma virus (HPV) related oropharyngeal squamous cell carcinoma (OPSCC) there is a rationale for finding ways to de-escalate treatment strategies. This review aims to test the hypothesis that TORS is a meaningful adjunct in the diagnostic (and therapeutic) pathway in CUP in head and neck. METHODS: A structured search of the literature was performed with the search terms 'TORS'and 'Carcinoma of Unknown Primary'. RESULTS: 274 cases of CUP in which TORS was used were identified for further analysis. Work up for CUP was comparable in all series with regard to physical examination, fine and/ or gross needle examination of cervical nodes, fiber optic endoscopy, imaging and robot assisted mucosectomy of the base of tongue (BOT). Identification rate of the primary tumor was 72% on average (range 17- 90%) and 55- 96% were HPV positive. Clear margins were achieved in 60% (range 0-85%) of resected occult tumors. Complication rate of TORS BOT mucosectomy was low with mainly grade I-III sequelae according to ClavienDindo. CONCLUSIONS: TORS seems to be a useful and safe adjunct in the diagnostic and therapeutic pathway in case of CUP in an era of increasing incidence of HPV positive OPSCC.