Abstract
Objectives
To evaluate the prognostic value of the number of imaging-detected lymph node metastases (iLNM) in human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma (OPSCC), addressing the discrepancy between clinical and pathological N staging.Materials and methods
We retrospectively enrolled consecutive patients with HPV-associated OPSCC between January 2014 and December 2024. Lymph node metastases were defined as nodes with SUVmax ≥ 3.5 or Node-RADS score ≥ 3. Two readers evaluated iLNM number, nodal SUVmax, and imaging-detected extranodal extension (iENE). Kaplan-Meier analysis was used to estimate 5-year overall survival (OS) and event-free survival (EFS; recurrence or disease-related death), stratified by clinical stage (cStage, UICC 9th edition), nodal SUVmax, iLNM number, and iENE. Firth-penalized Cox proportional hazards models were used for univariable and multivariable analyses.Results
Sixty-eight patients (median age, 66; male:female = 55:13) were included. The 5-year OS and EFS were 80% and 77%, respectively. The primary Firth-penalized Cox model showed that iLNM ≥ 5 was associated with poorer OS (hazard ratio (HR), 11.4; 95% confidence interval [CI], 3.1-44.5) and EFS (HR, 6.5; 95% CI, 2.0-20.1). A sensitivity analysis additionally adjusting for cStage (III) yielded similar effect estimates for both OS (HR, 10.7; 95% CI, 2.6-46.0) and EFS (HR, 7.7; 95% CI, 2.0-27.2), supporting the consistency of the observed association after clinical adjustment.Conclusion
The number of iLNM may serve as a prognostic imaging biomarker for risk stratification in HPV-associated OPSCC, aligning with pathological nodal staging and improving clinical prognostic assessment.Key points
Question Discrepancies between clinical and pathological nodal staging in the 9th UICC TNM classification for HPV-associated oropharyngeal squamous cell carcinoma (OPSCC) remain an unsolved clinical problem. Findings The number of imaging-detected lymph node metastases (iLNM), defined as lymph nodes with SUVmax ≥ 3.5 or Node-RADS score ≥ 3, was identified as an independent prognostic factor in HPV-associated OPSCC. Clinical relevance Incorporating the number of iLNM into clinical nodal staging, using an approach similar to pathological nodal staging, may improve risk stratification and enable more accurate prognostic assessment in HPV-associated OPSCC.