The value of tongue base mucosectomy in the work-up of squamous cell carcinoma of unknown primary: A Danish national cohort study

INTRODUCTION: Squamous cell carcinoma of unknown primary in the head and neck (HNSCCUP) remains a diagnostic challenge. Tongue base mucosectomy by transoral robotic surgery (TORS-TBM) can increase the diagnostic yield and de-intensify treatment. However, the added value of TORS-TBM as an adjunct to work-up programs for HNSCCUP is unclear. Furthermore, the optimal extent of the procedure and selection criteria remain to be established.

AIM: The primary aim of the present study was to assess the diagnostic yield of TORS-TBM as a supplement to a standardized work-up program, using the Danish national guidelines as an example. Secondary aims include predictive values of HPV-testing and PET/CT.

METHODS: This was a national multicenter observational cohort study including all patients diagnosed with HNSCCUP from January 2013 to December 2019, who subsequently underwent TORS-TBM. In most cases HPV status was based on dual testing (p16 and HPV-DNA). Predictive values of PET/CT and HPV status were calculated.

RESULTS: A total of 100 consecutive patients underwent TORS-TBM; 93 total TBMs and 7 unilateral TBMs. The primary tumor was detected in 49 % (49/100) of patients. The detection rate was 58 % (47/81) in patients with HPV-associated disease (PPV of HPV status) and 11 % (2/19) in patients with HPV-independent disease. The NPV of HPV status was 89 %. The PPV and NPV of PET/CT was 53 % and 52 %, respectively.

CONCLUSION: Adding total TORS-TBM to the current Danish guideline-based work-up program on HNCCCUP patients with HPV-associated disease significantly improved the diagnostic yield.