Radiographic nodal prognostic factors in stage I HPV-related oropharyngeal squamous cell carcinoma.

Background: The updated AJCC Cancer Staging Manual groups all p16-positive oropharyngeal squamous cell carcinoma (OPSCC) with unilateral nodal involvement within 6 cm into the new clinical N1 classification, consolidating a heterogeneous group of disease with varying radiographic findings.

Methods: A central radiological review was conducted identifying 233 patients with stage I node-positive (cT1-2N1) disease who underwent definitive concurrent chemoradiation. Factors evaluated included lymph node size, low-neck lymphadenopathy, retropharyngeal lymphadenopathy, overt radiographic extracapsular extension, and matted lymphadenopathy.

Results: On multivariate analysis adjusted for age, smoking history, and chemotherapy regimen, low-neck lymphadenopathy (hazard ratio (HR) = 6.55; P < .001) and retropharyngeal lymphadenopathy (HR = 3.36; P = .009) predicted for inferior progression-free survival (PFS). low-neck lymphadenopathy (HR = 6.38; P = .001) and retropharyngeal lymphadenopathy (HR = 3.32; P = .02) also predicted for inferior overall survival (OS). All other radiographic characteristics showed no prognostic impact for PFS or OS.

Conclusions: This analysis suggests that caution should be advised against de-intensification efforts among patients with stage I node-positive p16-positive OPSCC with low-neck lymphadenopathy or retropharyngeal lymphadenopathy.