The prognostic value of metastatic lymph node number and ratio in oesophageal squamous cell carcinoma patients with or without neoadjuvant chemoradiation

We aim to evaluate the prognostic value of metastatic lymph node number (MLN) and ratio (MLR) in oesophageal squamous cell carcinoma (OSCC) patients with or without neoadjuvant chemoradiation. Two thousand one hundred and fifty-one OSCC patients receiving oesophagectomy with (n = 850) or without (n = 1301) neoadjuvant chemoradiation were included. The MLN was categorized into 0 (N0), 1-2 (N1), 3-6 (N2) and more than 7 (N3); the MLR was categorized into 0, 0-0.2 and > 0.2. The prognostic value was evaluated with survival analysis using the Cox proportional hazards regression model and the Kaplan-Meier method. In patients without neoadjuvant chemoradiation, the 3-year overall survival rates were 54.8, 34.4, 21.8 and 6.5% with MLN = 0, 1-2, 3-6 and more than 7, respectively (P < 0.001). The 3-year overall survival rates were 54.7, 31.2 and 14.2% with MLR = 0, 0-0.2 and more than 0.2, respectively (P < 0.001). In patients with neoadjuvant chemoradiation, the 3-year overall survival rates were 49.0, 28.4, 12.5 and 0.0% with MLN = 0, 1-2, 3-6 and more than 7, respectively (P < 0.001). However, the survival curves of MLN = 3-6 and MLN a parts per thousand yen7 overlapped on the Kaplan-Meier plots. In contrast, MLR demonstrated good ability to show the survival differences on the Kaplan-Meier plots. The 3-year overall survival rates were 48.9, 27.3 and 0.0% with MLR = 0, 0-0.2 and more than 0.2, respectively (P < 0.001). Both MLN and MLR were significant prognostic factors in OSCC patients regardless of neoadjuvant chemoradiation. But in patients with neoadjuvant chemoradiation, the survival rates were similar between ypN2 and ypN3 patients, suggesting that there was no necessity of separating patients into ypN2 and ypN3 stages.