Tumor budding and lymphovascular invasion as prognostic factors in p16-positive oropharyngeal squamous cell carcinomas: Molecular Diagnostics

Background: We aimed to validate the prognostic significance of tumor budding (TB) in p16-positive oropharyngeal squamous cell carcinomas (OPSCC). Methods: We analyzed digitized H&E-stained slides from a multicenter cohort of five large university centers consisting of n = 275 cases of p16-positive OPSCC. We evaluated TB along with other histological parameters (morphology, tumor-stroma-ratio, lymphovascular invasion (LVI), perineural invasion) and calculated survival outcomes using both univariate and multivariate analyses. Results: TB was identified as an independent prognostic parameter, with TB-high cases showing inferior outcomes in univariate (HR: 3.08, 95%-CI: 1.71–5.54) and multivariate analyses (HR: 4.03, 95%-CI: 1.65–9.83). Similarly, LVI remained an independent prognostic factor (HR: 3.00, 95%-CI: 1.22–7.38). A combined classification including TB and LVI stratified cases into low-, intermediate- and high-risk categories. We could not detect correlations between TB and the number of lymph node metastases or between TB and an extracapsular extension of lymph node metastases. Conclusions: In addition to LVI, we could identify TB as an independent prognostic factor in p16-positive OPSCC in this multicenter study cohort. Thus, evaluating TB along with LVI in a combined scheme for prognostication might help to establish a more personalized treatment regimen for patients with p16-positive OPSCC.