Importance: The diagnostic and therapeutic approach to patients with head and neck squamous cell carcinoma of unknown primary (CUP) has recently been transformed with the introduction of transoral robotic surgery (TORS). Whether the current paradigm of performing base of tongue mucosectomy for primary site identification applies in a human papilloma virus (HPV) negative subset of patients is unknown.
Objective: To analyze the role of TORS base of tongue mucosectomy in a cohort of patients with HPV negative CUP.
Design, Setting, and Participants: A retrospective database review from 2012-2018 was performed at two large tertiary centers to study patients with HPV negative CUP that underwent TORS base of tongue mucosectomy. HPV status was determined using p16 and/or HPV-DNA testing. Patients were included that had squamous cell carcinoma metastatic to the lateral neck based on fine needle aspiration or open biopsy. Preoperatively, all patients were classified as having an unknown primary based on normal clinical and flexible endoscopic exam, normal operative endoscopy, non-localizing imaging, and tonsillectomy. All patients underwent robotic base of tongue mucosectomy.
Main Outcome Measures: The primary outcome measure was the incidence of pathologic identification of a mucosal primary.
Results: In total, 180 patients with CUP that underwent TORS BOT mucosectomy were identified for further analysis. Of this subset, 23/180 (12.7%) were p16 and/or HPV-DNA negative based on biopsy of the nodal metastasis. Median age was 60 years at the time of diagnosis and 18/23 (78.2%) were male. Pathologic analysis of the BOT specimens showed a primary tumor in only 3/23 (13.0%) of patients.
Conclusion and Relevance: Despite prior evidence suggesting a high rate of primary site identification in HPV related disease, TORS base of tongue mucosectomy may not be indicated for HPV negative CUP based on a low likelihood of finding the primary.