Prognostic Significance of Lymph Node Ratio in Metastatic Cutaneous Squamous Cell Carcinoma of the Head and Neck.

Abstract

The prognostic variables in patients with metastatic cutaneous nodal squamous cell carcinoma (SCC) are well documented; however, the relationship between lymph node ratio (LNR) and outcome is not well researched. LNR represents the ratio of positive lymph nodes to total excised lymph nodes. We analyzed the correlation between LNR and outcome in patients who have undergone surgery for metastatic cutaneous nodal SCC of the head and neck. Analysis was performed on retrospectively collected data, identifying patients who underwent surgery at Westmead Hospital, Sydney. Pathology reports were reviewed to ascertain LNR. A log-rank test identified a specific LNR value to compare time to disease progression (TTDP) and overall survival (OS). Multivariate proportional hazard regression models were used to review outcome. In total, 193 males and 45 females with a median of age 68years were identified, with a mean recorded LNR of 0.15. On multivariate analysis, an LNR cutpoint of 0.21 was a significant predictor of decreased TTDP [hazard ratio (HR) 2.34, 95% confidence interval (CI) 4.40-0.49; p=0.009] and OS (HR 2.75, 95% CI 1.57-4.82; p<0.001). Forty-nine of 238 patients (21%) developed recurrence, with most recurrences being regional (29 of 49; 59%). A total of 17% of patients with an LNR ≤0.21 recurred compared with 40% for patients with an LNR >0.21. LNR is potentially an independent predictor of outcome in patients with metastatic cutaneous nodal SCC. The clinical relevance of this finding requires further validation.