Comparison of mean survival between the groups with and without nodal metastasis Nodal metastasis Mean survival (month) 95% CI p N (-) 51.0 39.9 - 62.2 0.0357 N (+) 20.2 14.1 - 26.2 Comment: Survival of the group without nodal metastasis is longer than that of the group with nodal metastasis, the difference is statistically significant with p<0.05 - Cum survival in line with quantity of metastatic nodes: The rates of survival after one year of N0, N1, N2 and N3 are 85, 6%, 70, 9%, 68, 6% and 50% respectively.