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

Abstract

• Work-up in head and neck cancer of unknown primary (HNSCCUP) followed guidelines. • Tongue base mucosectomy (TBM) increased the diagnostic yield by 58 % in HPV + HNSCCUP. • Total TBM by transoral robotic surgery (TORS) performed in 93 % of the cohort. • HPV status was a stronger predictor of oropharyngeal primary site than PET/CT scan. • First ever populations-based study on TORS-TBM in HNSCCUP (n = 100). 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. 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. 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. 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. 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.