Advancing Education, Research, and Quality of Care for the Head and Neck oncology patient.
Importance: In the recent decades, there has been a substantial rise in the incidence of oropharyngeal squamous cell carcinoma (OPSCC) caused by oncogenic subtypes of the human papilloma virus (HPV). Luckily, oncologic outcomes remain favorable for this population. Select patients with early-stage disease can even be candidates for surgical therapy alone. In this group, adverse features noted at time of surgical extirpation often drive decision making for adjuvant therapy. The definition of adverse features for this distinct oncologic entity continues to evolve and remains an area of active research.
Objective: Investigate the prognostic significance of lymph node yield (LNY) and lymph node ratio (LNR) in patients with early-stage HPV-mediated OPSCC treated with surgery alone.
Design, Setting, and Participants: Data was collected retrospectively from four tertiary care academic medical centers. HPV-mediated OPSCC patients that underwent definitive surgical therapy with ipsilateral neck dissection alone were identified. Patients that received adjuvant therapy were excluded.
Exposure: For the entire cohort, number of lymph nodes recovered (lymph node yield) was assessed. For patients with pathologic nodal disease, the ratio of positive nodes against total lymph nodes recovered was evaluated.
Outcome(s) and Measure(s): Disease-free survival and locoregional recurrence were assessed via both non-parametric Kaplan-Meier estimator and semi-parametric Cox proportional hazard models.
Results: For the 185 patients included in this study, univariate analysis revealed LNY to have a protective effect on disease free survival with a HR of 0.98 (95% CI, 0.97 – 0.99; p = 0.04). Amongst the 132 patients with positive nodal disease, LNR was associated with increased hazard of regional recurrence (1.07 HR; 95% CI, 1.04–1.11; p<0.001), locoregional recurrence (1.06 HR; 95% CI, 1.04–1.08); p<0.001), and recurrence or death (1.06 HR; 95% CI, 1.03-1.08; p<0.001). Recursive partitioning analysis identified LNY greater than 20 to be a distinct prognostic subgroup for disease free survival with a HR of 0.52 (95% CI, 0.45-0.60; p<0.001). Similarly in patients with pathologic nodal disease, Scaled LNR greater than 3.25 was a distinct prognostic subgroup for disease free survival with a HR of 1.83 (95% CI, 1.51-2.20; p<0.001). These associations persisted on multivariate analysis controlling for PNI, LVI, ENE, margin status, and tumor dimension.
Conclusions and Relevance: Quality of neck dissection as assessed by LNY and nodal disease burden quantified via LNR can be utilized as valuable risk stratification tools in patients with HPV-mediated OPSCC.