Table 1. Baseline characteristics of the study population.
| Variables | Discovery phase | Validation phase | All samples (N = 825) | |||
| Harvard (N = 96) | Spain (N = 183) | Norway (N = 133) | Sweden (N = 81) | TCGA (N = 332) | ||
| Age (years) | 67.1 ± 9.9 | 65.6 ± 10.5 | 65.5 ± 9.3 | 66.1 ± 10.4 | 65.4 ± 9.8 | 65.7 ± 9.6 |
| Gender, n (%) | ||||||
| Female | 50 (52.1) | 89 (48.6) | 62 (46.6) | 35 (43.2) | 152 (45.8) | 388 (47.0) |
| Smoking status, n(%) | ||||||
| Never | 17 (17.7) | 28 (15.6) | 17 (12.8) | 17 (21.0) | 47 (14.6) | 126 (15.5) |
| Former | 52 (54.2) | 97 (53.9) | 74 (55.6) | 39 (48.1) | 194 (60.2) | 456 (56.2) |
| Current | 27 (28.1) | 55 (30.6) | 42 (31.6) | 25 (30.9) | 81 (25.2) | 230 (28.3) |
| Clinical stage, n(%) | ||||||
| I | 72 (75.0) | 151 (82.5) | 93 (69.9) | 74 (91.4) | 230 (69.3) | 620 (75.2) |
| II | 24 (25.0) | 32 (17.5) | 40 (30.1) | 7 (8.6) | 102 (30.7) | 205 (24.8) |
| Chemotherapy, n(%) | ||||||
| Yes | 4 (4.2) | 14 (7.7) | 31 (23.3) | 4 (4.9) | 20 (6.0) | 73 (8.8) |
| No | 92 (95.8) | 142 (77.6) | 102 (76.7) | 50 (61.7) | 109 (32.8) | 495 (60.0) |
| Unknown | 0 | 27 | 0 | 27 | 203 | 257 |
| Radiotherapy, n(%) | ||||||
| Yes | 12 (12.5) | 8 (8.9) | 1 (0.8) | 0 (0.0) | 6 (4.7) | 27 (4.8) |
| No | 84 (87.5) | 148 (91.1) | 132 (99.2) | 54 (100.0) | 123 (95.3) | 541 (95.2) |
| Unknown | 0 | 27 | 0 | 27 | 203 | 257 |
| Adjuvant therapy, n(%) | ||||||
| Yes | 14 (14.5) | 21 (13.4) | 32 (24.0) | 4 (7.4) | 25 (19.3) | 96 (16.9) |
| No | 82 (85.5) | 135 (86.6) | 101 (76.0) | 50 (92.6) | 104 (80.7) | 472 (83.1) |
| Unknown | 0 | 27 | 0 | 27 | 203 | 257 |
| Survival year | ||||||
| Median survival year | 7.1 | 9.6 | 7.2 | 7.1 | 4.4 | 7.4 |
| Censored ratea, % | 0.3 | 58.5 | 68.4 | 40.7 | 80.7 | 63.4% |
a Censored rate is proportion of samples lost to follow-up or alive at end of the study.
TCGA: The Cancer Genome Atlas