Table 3. Multivariate analysis of survival on clinical and pathologic factors.

Variables	Risk ratio (95% CI)	P value
Stage Ia	0.14 (0.04–0.50)	0.002*
Stage IIa	0.26 (0.11–0.58)	0.001*
Age	–	0.852
Sex	–	0.596
Histology homology	–	0.382
Lymph node metastasis	–	0.285
Lymphovascular invasion	–	0.771
Tumor location	–	0.805
Adjutant therapy	–	0.191

^a, stage III was set as reference (RR=1.00). *, P<0.05.