Characteristics of the training cohort
| (A) Training | Lung cancer (n=50) | Benign nodules (n=42) | P value* |
| Male, n (%) | 25 (50) | 28 (67) | 0.162 |
| Age (years), mean (SD) | 63.6 (7.1) | 65.2 (6.9) | 0.261 |
| Current smoker, n (%) | 32 (64) | 19 (45) | 0.111 |
| Pack-years, mean (SD) | 60.35 (24.11) | 61.81 (22.81) | 0.766 |
| Years since quit smoking, mean (SD) | 1.52 (2.88) | 3.25 (3.95) | 0.020 |
| Nodule size in diameter (mm), mean (SD) | 13.43 (6.14) | 9.74 (6.69) | 0.007 |
| Nodule number, n (%)† | 0.203 | ||
| Solid | 28 (56) | 34 (81) | |
| Non-solid/mixed | 22 (44) | 8 (19) | |
| Vessel number, mean (SD) | 9.22 (9.48) | 2.26 (2.21) | <0.001 |
| (B) Validation | Lung cancer (n=44) | Benign nodules (n=82) | P value* |
| Male, n (%) | 23 (52) | 48 (59) | 0.626 |
| Age, mean, years (SD) | 65.23 (9.62) | 66.93 (7.54) | 0.313 |
| Current smoker, n (%) | 37 (84) | 36 (44) | <0.001 |
| Pack-years, mean (SD)‡ | 49.41 (22.79) | 49.49 (22.0) | 0.985 |
| Years since quit smoking, mean (SD) | 0.477 (1.50) | 3.037 (4.33) | <0.001 |
| Nodule size in diameter (mm), mean (SD) | 18.86 (7.12) | 11.57 (5.76) | <0.001 |
| Nodule number, n (%)† | 0.981 | ||
| Solid | 28 (78) | 54 (68) | |
| Non-solid/mixed | 8 (22) | 25 (32) | |
| Vessel number, mean (SD) | 18.57 (5.21) | 3.02 (3.98) | <0.001 |
*Two-sided p values were based on t-test and χ2 test for continuous and categorical variables, respectively.
†Nodule type was unmeasured for 11 subjects (8 with cancer).
‡Pack-years was unmeasured for 5 subjects (4 with cancer).