Is lymph node ratio a prognostic factor for patients with oral squamous cell carcinoma?

Publication date: Available online 2 February 2019

Source: Journal of Oral and Maxillofacial Surgery

Author(s): Kenji Yamagata, Satoshi Fukuzawa, Naomi Kanno, Fumihiko Uchida, Toru Yanagawa, Hiroki Bukawa

ABSTRACT

Purpose

Lymph node ratio (LNR), defined as the ratio of positive resected lymph nodes (LNs) to the total number of resected LNs, predicts survival for some solid tumors. We investigated the value of LNR in the prognosis and postsurgical management of oral squamous cell carcinoma (OSCC).

Patients and methods

We designed a retrospective cohort study and enrolled a sample of patients who were diagnosed with OSCC and treated by neck dissection (ND). The predictor was the LNR and outcome variable was overall survival (OS). Other variables were included dissection type, postsurgical management, number of positive LNs, pN stage, nodal disease area, extracapsular spread, perineural invasion, vascular invasion and lymph duct invasion. Differences in OS rate a were analyzed by log-rank test. A Cox proportional hazards model was used to adjust for the effects of potential confounders. Differences with a P value less than 0.05 were considered statistically significant.

Results

In 95 patients with OSCC, LNR cut-off value for predicting overall OS was 0.04 (area under curve 0.705, P=0.010). There was significant difference in OS when patients were stratified according to LNR, with a rate of 90.5% for low-LNR patients and 68.8% for high-LNR patients (P=0.014). Univariate analyses revealed close correlations between OS and LNR, pT stage, the number of positive lymph nodes, and the nodal disease area (levels IV and V). Cox multivariate analysis identified LNR (HR 2.889, 95% CI 1.032–8.087; P=0.043) and the area of nodal disease (levels IV, V; HR 5.149, 95% CI 1.428–18.566; P=0.012) as independent predictive factors for OS. The OS differed significantly between high-LNR and low-LNR patients who were treated by surgery alone (P=0.027).

Conclusions

As a predictive factor, high LNR (≥0.04) was associated with diminished survival, and intensive adjuvant therapy may improve the prognosis for patients with high LNR.

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