Baseline characteristics of patients with clinically detected, stage I untreated non-small cell lung cancer
| Characteristic, N (%) | Study population n=2197 | 95% CI |
| Age (years) | ||
| 65–74 | 725 (33) | 31 to 35 |
| 75–84 | 1091 (50) | 48 to 52 |
| >85 | 381 (17) | 16 to 19 |
| Female | 1118 (51) | 49 to 53 |
| Married | 864 (39) | 37 to 41 |
| Race/ethnicity | ||
| White | 1767 (80) | 79 to 82 |
| Black | 254 (12) | 10 to 13 |
| Hispanic | 74 (3) | 3 to 4 |
| Other | 102 (5) | 4 to 6 |
| Median income | ||
| First quartile* | 666 (30) | 28 to 32 |
| Second quartile | 575 (26) | 24 to 28 |
| Third quartile | 528 (24) | 22 to 26 |
| Fourth quartile | 428 (19) | 18 to 21 |
| Diagnostic workup | ||
| CT chest | 2140 (97) | (97 to 98) |
| Positron emission tomography (PET) | 306 (14) | (13 to 15) |
| Mediastinoscopy | 34 (2) | (1 to 2) |
| COPD | 1042 (47) | 45 to 50 |
| Year of diagnosis | ||
| 1992–1999 | 980 (45) | 43 to 47 |
| 2000–2009 | 1217 (55) | 53 to 57 |
| Histology | ||
| Adenocarcinoma | 903 (41) | 39 to 43 |
| Squamous cell | 875 (40) | 38 to 42 |
| Large cell | 129 (6) | 5 to 7 |
| Other | 290 (13) | 12 to 15 |
| Tumour size (mm)† | ||
| <15 | 80 (4) | 3 to 6 |
| 15–24 | 369 (17) | 15 to 18 |
| 25–34 | 486 (22) | 20 to 24 |
| 35–44 | 313 (14) | 13 to 16 |
| >45 | 377 (17) | 16 to 19 |
*Lowest income quartile
†Five hundred and seventy-two (26%) with unknown tumour size.