Ratio of Metastatic Lymph Nodes: A Significant Prognostic Factor in Patients with Oral Squamous Cell Carcinoma

Abstract

Background: One of the significant prognostic factors for survival in squamous cell carcinoma of the oral cavity is the presence or absence of cervical metastasis. Thus, management of cervical lymph nodes becomes a vital component of the overall treatment strategy for patients with cancers of the head and neck. The aim of this study was to investigate the prognostic value of the ratio of metastatic lymph nodes in patients with oral squamous cell carcinoma. Methods: A retrospective analysis of 225 biopsy-proven oral squamous cell carcinoma (OSCC) patients with T1-T4a status of the primary tumor was done. All cases had a history of surgical excision of the primary lesion and neck dissection with a follow-up period of two years. Primary tumor sites include viz buccal mucosa, tongue, alveolus, gingivo-buccal sulcus and retromolar trigone. Patients with loco-regionally advanced disease and a history of any previous surgery or radio-therapeutic treatment of the head and neck were excluded from the study. Locoregional recurrence, disease-free survival, and the associations between clinicopathological features and recurrence were analysed using univariate and multivariate analysis. p-value ≤ 0.001 was found to be significant. Survival curves were plotted using the Kaplan-Meier method for 5-year disease-free survival. Results: The patients with positive lymph nodes were divided into high- or low-risk groups using the best nodal parameter cut-off values (0.06). Our univariate analysis showed a significant correlation between locoregional recurrence and type of neck dissection, pN classification, staging, extranodal extension, perineural invasion, and ratio of metastatic lymph nodes (RML). However, on multivariate analysis, RML showed an independent prognostic predictor (p= 0.04) for locoregional recurrence. Conclusion: The findings of our study suggest that RML is a strong independent predictor of prognosis in patients with oral squamous cell carcinoma.