Demographic and clinical characteristics of the study cohort
| Characteristic | Subjects n | Median (range) | Frequency |
| Age yrs | 1277 | 66 (32–90) | |
| Male sex y/n | 1277 | 1096/181 | |
| Current smokers y/n | 1277 | 993/284 | |
| Education E/ML/MH/H/U | 1277 | 508/531/156/66/16 | |
| Previous lung diseases y/n | 1277 | 517/760 | |
| Previous extra-pulmonary diseases y/n | 1277 | 949/328 | |
| History of other cancers y/n | 1277 | 137/1140 | |
| Referral delay# | 1277 | 2 (0–48) | |
| Diagnostic period¶ | 1277 | 319/319/320/319 | |
| ECOG PS 0/1/2/3/4 | 1277 | 143/512/447/149/26 | |
| Weight loss+ | 1256 | 95 (59–125) | |
| Tumour cell type ES/S/A/L/U | 1277 | 496/144/293/82/262 | |
| Serum blood tests | |||
| Haemoglobin g·dL−1 | 1271 | 13.8 (6.6–20.0) | |
| White blood cells n·mm−3 | 1271 | 8550 (2890–36400) | |
| Platelets n·mm−3 | 1274 | 285000 (72000–982000) | |
| GOT mg·dL−1 | 1269 | 19 (5–550) | |
| GPT mg·dL−1 | 1267 | 19 (3–765) | |
| Lactate dehydrogenase mg·dL−1 | 1212 | 389 (81–10.120) | |
| Creatinine mg·dL−1 | 1269 | 0.9 (0.4–4.8) | |
| CEA ng·mL−1 | 1227 | 3 (0–7584) | |
| TPA U·L−1 | 1217 | 130 (10–5203) | |
| Stage of disease 0/1a/1b/2a/2b/3a/3b/4 | 1277 | 1/91/145/11/41/203/324/461 | |
| TNM staging factors | |||
| T factor 0/1/2/3/4 | 1277 | 1/176/452/183/465 | |
| N factor 0/1/2/3 | 1277 | 480/120/446/231 | |
| M factor 0/1 | 1277 | 816/461 | |
| Lung metastases y/n | 1277 | 184/1093 | |
| Brain metastases y/n | 1277 | 140/1137 | |
| Liver metastases y/n | 1277 | 118/1159 | |
| Renal/suprarenal gland metastases y/n | 1277 | 100/1177 | |
| Bone metastases y/n | 1277 | 120/1157 | |
| Primary treatment P/C/R/S | 1277 | 434/541/69/233 | |
| Follow-up time weeks | 1277 | 30.7 (1.3–722.6) | |
| Status alive/dead | 1277 | 238/1039 |
y: yes; n: no; E: elementary; ML: middle-lower class; MH: middle-higher class; H: high school; U: university; ECOG PS: Eastern Cooperative Oncology Group performance status; ES: epidermoid or squamous cell cancer; S: small cell cancer; A: adenocarcinoma; L: large cell anaplastic cancer; U: unclassified or mixed cell type; GOT: glutamic oxalacetic transaminase; GPT: glutamic pyruvic transaminase; CEA: carcinoembryonic antigen; TPA: tissue polypeptide antigen; P: palliative and supportive care; C: chemotherapy; R: radio-chemotherapy; S: surgical resection. #: months from the first symptom of lung cancer (alarming symptom) to the specialist referral; ¶: quartiles of the distribution of the dates of diagnosis (Period I: no. 319 (Jan. 1989–May 1992); Period II: no. 319 (Jun. 1992–Sep. 1995); Period III: no. 320 (Oct. 1995–May 1999); Period IV: no. 319 (Jun. 1999–Oct. 2002)); +: body weight at diagnosis in % of the usual weight