Table 1. Characteristics of the study population.

Clinical parameters and outcome variables	Study population
Age
<55 years old	32 (29.9%)
55–65 years old	42 (39.3%)
>65 years old	33 (30.8%)
Gender
Male	94 (87.9%)
Female	13 (12.1%)
Tumour differentiation
Well differentiated	44 (41.1%)
Moderately differentiated	51 (47.7%)
Poorly differentiated	12 (11.2%)
pT
pT1	34 (31.8%)
pT2	12 (11.2%)
pT3	61 (57.0%)
pN
N−	66 (61.7%)
N+	41 (38.3%)
Vascular invasion
No	72 (67.3%)
Yes	35 (32.7%)
Local recurrence
No	71 (66.4%)
Yes	36 (33.6%)
Metastasis occurrence
No	56 (52.3%)
Yes	51 (47.7%)
Postoperative treatment
No (pot− group)	59 (55.1%)
Yes (pot+ group)	48 (44.9%)
Total	107 (100%)