| Variable | Patients n |
| Sex | |
| Male | 210 |
| Female | 40 |
| Age yrs | |
| <60 | 89 |
| 60–65 | 82 |
| 65–70 | 30 |
| ≥70 | 49 |
| Education level | |
| No/primary level | 181 |
| Higher education | 59 |
| Missing | 10 |
| Histology | |
| ADC | 133 |
| SCC | 110 |
| Others | 7 |
| Asbestos exposure | |
| None | 191 |
| Yes | 57 |
| Missing | 2 |
| pT | |
| T1 | 76 |
| T2 | 150 |
| T3 | 15 |
| T4 | 8 |
| Missing | 1 |
| pN | |
| N0 | 173 |
| N1 | 65 |
| N2 | 2 |
| NX | 9 |
| Missing | 1 |
| Past pulmonary illness | |
| No | 110 |
| Yes | 138 |
| Missing | 2 |
| Smoking status# | |
| Current smoker | 152 |
| Former smoker | 86 |
| Never-smoker | 11 |
| Missing | 1 |
| Total | 250 |
ADC: adenocarcinoma; SCC: squamous cell carcinoma; pT: pathological tumour score; pN: pathological node score. #: former smokers were patients who had quit smoking at least 2 yrs before interview and current smokers were patients who were smokers in the last 2 yrs before interview.