Survival outcome analysis
The Kaplan-Meier survival curve of both groups, including the patients with the nodal volume of <3.95 cm3 and ≥3.95 cm3, were identified and compared using the log-rank test. Overall survival and distant metastasis-free survival were significantly different between the nodal volume of <3.95 cm3 and ≥3.95 cm3 groups (p<0.001 and p=0.005, respectively), but not for the disease-free survival (p=0.241). (Figure 3)
From 2-year survival analysis, overall survival rate of patients with the nodal volume of of <3.95 cm3 and ≥3.95 cm3 were 50% (95%CI = 0.3130-0.6612) and 12.5% (95% CI = 0.0458-0.2461), respectively. The metastasis-free survival rate of the nodal volume of <3.95 cm3 and ≥3.95 cm3 groups were 90% (95%CI = 0.6707-0.9763) and 48% (95%CI = 0.2359-0.6978), respectively, while for the recurrent-free survival rate were 82.5% (95%CI = 0.5952 -0.9311) and 55.49% (95%CI = 0.2426-0.7827), respectively.