Table 1.
Patient demographics and clinical background by age group
| Variable | All patients | <75 years | ≥75 years | Difference <75 years vs ≥75 years |
| Patients, n (%) | 901 (100.0) | 723 (100.0) | 178 (100.0) | – |
| Gender, n (%) | ||||
| Male | 651 (72.3) | 519 (71.8) | 132 (74.2) | 0.5754* |
| Female | 250 (27.7) | 204 (28.2) | 46 (25.8) | |
| Age (years), median (range) | 67.0 (30.0–90.0) | 65.0 (30.0–74.0) | 78.0 (75.0–90.0) | – |
| BMI (kg/m2), median (range) | 21.4 (12.9–36.9) | 21.4 (12.9–36.9) | 21.3 (13.6–30.7) | 0.4087† |
| Disease stage at diagnosis of NSCLC, n (%) | ||||
| IA−IIIA | 302 (33.5) | 232 (32.1) | 70 (39.3) | 0.1625* |
| IIIB | 102 (11.3) | 86 (11.9) | 16 (9.0) | |
| IV | 497 (55.2) | 405 (56.0) | 92 (51.7) | |
| ECOG PS, n (%) | ||||
| 0 | 193 (21.4) | 162 (22.4) | 31 (17.4) | 0.0253*‡ |
| 1 | 490 (54.4) | 379 (52.4) | 111 (62.4) | |
| 2 | 109 (12.1) | 93 (12.9) | 16 (9.0) | |
| 3 and 4 | 48 (5.3) | 33 (4.6) | 15 (8.4) | |
| Missing | 61 (6.8) | 56 (7.7) | 5 (2.8) | |
| Histological type, n (%) | ||||
| Squamous cell carcinoma | 221 (24.5) | 159 (22.0) | 62 (34.8) | 0.0017* |
| Adenocarcinoma | 610 (67.7) | 505 (69.8) | 105 (59.0) | |
| Other | 28 (3.1) | 21 (2.9) | 7 (3.9) | |
| Unclassified | 42 (4.7) | 38 (5.3) | 4 (2.2) | |
| Other primary malignant tumours, n (%) | 100 (11.1) | 77 (10.7) | 23 (12.9) | 0.4238*§ |
| Smoking history, n (%) | ||||
| Current smoker | 308 (34.2) | 253 (35.0) | 55 (30.9) | 0.5549* |
| Former smoker | 412 (45.7) | 328 (45.4) | 84 (47.2) | |
| Never smoker | 181 (20.1) | 142 (19.6) | 39 (21.9) | |
| EGFR mutation, n (%) | ||||
| Yes | 116 (12.9) | 94 (13.0) | 22 (12.4) | 0.8963*§ |
| No | 641 (71.1) | 524 (72.5) | 117 (65.7) | |
| Unknown | 144 (16.0) | 105 (14.5) | 39 (21.9) | |
| EGFR mutation subtype n (%) | ||||
| TKI sensitive (L858R or Del19) | 94 (10.4) | 76 (10.5) | 18 (10.1) | 0.5183* |
| TKI non-sensitive | 16 (1.8) | 14 (1.9) | 2 (1.1) | |
| ALK mutation, n (%) | ||||
| Yes | 11 (1.2) | 7 (1.0) | 4 (2.2) | 0.1194*§ |
| No | 603 (66.9) | 496 (68.6) | 107 (60.1) | |
| Unknown | 287 (31.9) | 220 (30.4) | 67 (37.6) | – |
| Metastasis, n (%) | 698 (77.5) | 569 (78.7) | 129 (72.5) | 0.0883*§ |
| Metastasis location, n (%) | ||||
| Liver | 104 (11.5) | 82 (11.3) | 22 (12.4) | 0.6954* |
| Lung | 244 (27.1) | 195 (27.0) | 49 (27.5) | 0.9250* |
| Bone | 256 (28.4) | 213 (29.5) | 43 (24.2) | 0.1654* |
| Brain | 201 (22.3) | 178 (24.6) | 23 (12.9) | 0.0006* |
| Adrenal glands | 83 (9.2) | 74 (10.2) | 9 (5.1) | 0.0303* |
| Other | 309 (34.3) | 262 (36.2) | 47 (26.4) | 0.0136* |
| Concomitant disease, n (%) | ||||
| Any | 647 (71.8) | 505 (69.8) | 142 (79.8) | 0.0091* |
| COPD | 109 (12.1) | 81 (11.2) | 28 (15.7) | 0.1227* |
| Pulmonary infection | 22 (2.4) | 18 (2.5) | 4 (2.2) | 1.0000* |
| Interstitial lung disease | 47 (5.2) | 34 (4.7) | 13 (7.3) | 0.1861* |
| Autoimmune disease | 16 (1.8) | 14 (1.9) | 2 (1.1) | 0.7509* |
| Hypertension | 316 (35.1) | 231 (32.0) | 85 (47.8) | 0.0001* |
| Diabetes | 155 (17.2) | 116 (16.0) | 39 (21.9) | 0.0756* |
| Dyslipidaemia | 122 (13.5) | 100 (13.8) | 22 (12.4) | 0.7138* |
| Albumin (g/dL), median (range) | 3.7 (1.5–4.8) | 3.7 (1.5–4.8) | 3.6 (1.9–4.6) | 0.0300† |
*Fisher’s exact test.
†Wilcoxon rank-sum test.
‡0 vs 1 vs 2 vs (3 and 4).
§Yes/positive vs no/negative.
BMI, body mass index; COPD, chronic obstructive pulmonary disease; ECOG PS, Eastern Cooperative Oncology Group Performance Status; EGFR, epidermal growth factor receptor; NSCLC, non-small cell lung cancer.