| Characteristic | Full sample(n = 139) | Malignant(n = 58) | Benign(n = 81) | p Value |
| Clinical | ||||
| Mean (SD) age at index test (years) | 67.1 (10.2) | 68.7 (8.2) | 66.0 (11.3) | 0.11 |
| Male | 133 (96) | 54 (93) | 79 (98) | 0.24* |
| Smoking history | ||||
| Current or former smoker | 123 (88) | 55 (95) | 68 (84) | 0.19 |
| Never smoker | 12 (9) | 3 (5) | 9 (11) | |
| Current smoker | 51 (37) | 24 (41) | 27 (33) | 0.67 |
| Former smoker | 65 (47) | 28 (48) | 37 (46) | |
| Mean (SD) pack-years¶ | 49.2 (31.4) | 51.8 (30.7) | 46.7 (32.1) | 0.42 |
| Mean (SD) years quit†† | 15.1 (13.1) | 12.0 (11.1) | 17.7 (14.2) | 0.09 |
| History of other cancer ⩽5 years previously | 25 (18) | 10 (17) | 15 (19) | 0.85 |
| History of other cancer >5 years previously | 19 (14) | 11 (19) | 8 (10) | 0.12 |
| Any history of lung cancer | 9 (7) | 3 (5) | 6 (7) | 0.74* |
| Radiological | ||||
| Nodule in right lung | 89 (64) | 39 (67) | 50 (62) | 0.50 |
| Location of nodule | 0.16 | |||
| Upper lobe | 74 (53) | 35 (60) | 39 (48) | |
| Middle or lower lobe | 62 (45) | 22 (38) | 40 (49) | |
| Median (range) nodule size (mm)** | 15.0 (7–30) | 20.0 (8–30) | 13.0 (7–30) | <0.001† |
| Nodule spiculated | 52 (37) | 35 (60) | 17 (21) | <0.001 |
| PET results positive (any uptake) | 57 (41) | 47 (81) | 10 (12) | <0.001 |
SD, standard deviation; PET, positron emission tomography. Data are presented as number (%) unless otherwise specified. Subcategories do not sum to 100% because the variable value was unknown or unspecified for the remainder of patients. Unless otherwise indicated, χ2 tests were performed for categorical variables and t tests were performed for continuous variables. Missing data were excluded from all statistical tests. *Fisher exact test. †Mann-Whitney U test. ‡N = 86 (pack-years unknown for 21 smokers). §Applies only to former smokers (N = 49). Years quit were unknown for 3 former smokers. ¶N = 100. Pack-years unknown for 23 smokers. **Only patients with SPN(s) measuring between 7 and 30 mm (inclusive) in diameter were eligible for this study. ††Applies only to former smokers (N = 61). Years quit unknown for 4 former smokers.