Period and rate of overall 36-month survival of patients with non-metastatic lymph nodes (46.1 ± 2.9 months and 73.0%) are higher than those of N1 nodal metastases (34.7 ± 2.6 months and 45.5%), and N1 + N2 nodal metastases (23.8 ± 4.9 months and 18.2%, p <0.001).