Important prognostic significance of lymph node density in patients with node positive oral tongue cancer

Background: Lymph node density (LND) has been described as a prognostic factor for survival in patients with head and neck squamous cell carcinoma, particularly of the oral cavity. The aim of this study was to determine the prognostic significance of LND in patients with node positive oral tongue squamous cell carcinoma (OTSCC).

Methods: Patients with pathological node positive OTSCC were identified in a retrospective review of prospectively collected data. The optimal cut-point for LND was determined using the minimum P-value method and the log-rank test. The impact of this LND cut-point on time to disease progression and overall survival was determined.

Results: In 72 patients with OTSCC, an LND of 14.3% was found to have the greatest separation using the log-rank test (P < 0.001). LND ≤14.3% was predicted for longer time to disease progression with a median time of 73 months compared to 9.4 months in patients with an LND >14.3% (hazard ratio: 3.43; 95% confidence interval: 1.76-6.70; P < 0.001). LND was also a significant predictor of overall survival with a median overall survival with LND ≤14.3% of 82.3 months, compared with 14.7 months in patients with an LND >14.3% (hazard ratio: 3.28; 95% confidence interval: 1.61-6.68; P = 0.001). Patients with an LND >14.3% experienced a higher rate of regional recurrence.

Conclusion: Our findings confirm the prognostic significance of LND in patients with node positive OTSCC, with a similar LND cut-point value to other published series. Improving regional control in these high-risk patients may improve outcome.