148 Predictors and outcomes of Contralateral Lymph node involvement in node positive oral squamous cell carcinoma: A retrospective analysis of 180 patients.

Contralateral lymph node metastasis (CLNM) is a poor prognostic factor in patients with oral squamous cell carcinoma (OSCC). There is limited data from India on this topic. The aim of this study was to evaluate the outcomes of contralateral positive cancer patients undergoing neck dissection in a tertiary hospital in India. We retrospectively reviewed the electronic medical records of 180 patients who had bilateral lymph nodes dissection for OSCC. Demographic, clinico-pathological and follow up data was abstracted directly from patients' electronic medical records. We analyzed the disease-free survival (DFS) and overall survival (OS) of these patients using a log-rank test (univariate) and cox proportional hazards model (multivariate). The median age of the cohort was 52 years (21-78 years) and comprised 125 males (69.4%). 83 (46.1%) patients had nodal metastasis on the contralateral side. Median follow up for patients who were alive at the time of analysis was 25.6 months (0.1- 130.1 months). Deeper lesion (depth 2.15 cm vs 1.70 cm, p=0.01), presence of lymphovascular invasion (LVI) (51.9% vs 31.4%, p=0.01), extranodal extension (ENE) (54% vs 34.4%, p=0.01) and nodal metastasis to ipsilateral level IV (83.3% vs 33.1%, p<0.01) predisposed to contralateral nodal metastasis. There were 92 disease failures in this cohort with 2 year DFS of 52%. Depth of invasion (DoI) [Hazard ratio (HR) 1.21, 95% confidence interval (CI) 1.02- 1.44, p=0.03), involved margins (HR 3.49, CI 1.83- 6.64, p<0.01), presence of perineural invasion (PNI) (HR 2.64, CI 1.54- 4.53, p <0.01), masticator space invasion (HR 2.10, CI 1.01- 4.08, p= 0.03) and presence of extranodal extension (ENE) in contralateral node (HR HR 2.29, CI 1.00- 5.29, p= 0.04) predicted poorer DFS on univariate analysis. On multivariate analysis, tongue as primary site(HR 0.49, CI 0.28- 0.85, p=0.01), involved margins (HR 2.66, CI 1.30- 5.43, p<0.01) and PNI (HR 2.62, CI 1.36- 4.99, p<0.01) affected the DFS significantly. There were 54 deaths in this cohort with a 2-year OS of 70.1%. Involved margins (HR 4.89, CI 2.17- 11.05, p<0.01), PNI (HR 3.11, CI 1.47- 6.61, p<0.01) and ENE (HR 1.77, CI 1.01- 3.07, p=0.04) were associated with a poorer OS on univariate analysis. On multivariate analysis, involved margins (HR 2.91, CI 1.22- 6.97, p=0.02) and PNI (HR 2.25, CI 1.02- 4.98, p=0.04) resulted in patients having poorer OS. This study provides valuable insights into the outcomes of patients with contralateral lymph nodal metastasis for patients who underwent curative intent surgery for oral squamous cell carcinoma. Deeper lesions, presence of lymphovascular invasion, extranodal extension and nodal metastasis to ipsilateral level IV predisposed to contralateral nodal metastasis. Primary site, involved margins and perineural invasion predicted the disease free survival, whereas involved margins and perineural invasion predicted overall survival in this cohort of patients. [Display omitted] [ABSTRACT FROM AUTHOR]