Table 1.

The clinical and pathological characteristics

Characteristics	Metformin (−)	Metformin ( +)	HR	95%CI	P-value
Gender
Male	404	64	0.951	0.680–1.331	0.770
Female	677	102
Age	58.23 ± 11.139	61.08 ± 10.765			0.002
> 65 years	293	101	1.731	1.233–2.430	0.001
≤ 65 years	788	65
Smoking
No	955	144	1.158	0.713–1.882	0.554
Yes	126	22
Tumor size (cm)	1.88 ± 1.409	1.73 ± 1.080			0.214
Residual
R0	1071	163	0.971	0.537–7.238	0.297
R1/2	10	3
Tumor location					0.098
Left	439	53
Right	628	110
Bilateral	14	3
Stage					0.191
0/I	883	146
II	78	8
III	96	8
IV	24	4
PDL1
( +)	558	44	0.338	0.235–0.487	< 0.001
(−)	523	122