Table 1.
Characteristics of training set and testing set. P-values were calculated by Chi-square test.
| Training set (%) | Testing set (%) | p-value | |
|---|---|---|---|
| No. of cases | 24,680 | 9,700 | |
| Year of diagnosis | 2004-2011 | 2012-2013 | |
| Age | 0.09 | ||
| < 65y | 9,559 (38.7) | 3,855 (39.7) | |
| ≥ 65y | 15,121 (61.3) | 5,845 (60.3) | |
| Gender | 0.9 | ||
| Male | 12,240 (49.6) | 4,803 (49.5) | |
| Female | 12,440 (50.4) | 4,897 (50.5) | |
| Race | 0.73 | ||
| White | 22,276 (90.3) | 8,779 (90.5) | |
| Black | 1,912 (7.7) | 727 (7.5) | |
| Other | 492 (2) | 194 (2) | |
| Hispanic origin | 0.91 | ||
| Non-Hispanic | 24,084 (97.6) | 9,463 (97.6) | |
| Hispanic | 596 (2.4) | 237 (2.4) | |
| Charlson/Deyo score | <0.001 | ||
| 0 | 13,288 (53.8) | 5,031 (51.9) | |
| 1 | 7,629 (30.9) | 3,061 (31.6) | |
| ≥ 2 | 3,763 (15.2) | 1,608 (16.6) | |
| Sequence number | 0.82 | ||
| 0 | 24,084 (97.6) | 9,463 (97.6) | |
| 1 | 527 (2.1) | 213 (2.2) | |
| ≥ 2 | 69 (0.3) | 24 (0.2) | |
| AJCC V8 TNM stage | <0.001 | ||
| IA | 1,207 (4.9) | 160 (1.6) | |
| IB | 463 (1.9) | 74 (0.8) | |
| IIA | 140 (0.6) | 18 (0.2) | |
| IIB | 853 (3.5) | 97 (1) | |
| IIIA | 1,548 (6.3) | 156 (1.6) | |
| IIIB | 902 (3.7) | 89 (0.9) | |
| IIIC | 208 (0.8) | 27 (0.3) | |
| IVA | 14,699 (59.6) | 6,655 (68.6) | |
| IVB | 4,660 (18.9) | 2,424 (25) | |
| Treatment | <0.001 | ||
| No surgery, no chemo, no radiation | 5,025 (20.4) | 2,213 (22.8) | |
| No surgery, no chemo, radiation done | 1,230 (5) | 520 (5.4) | |
| No surgery, chemo done, no radiation | 7,668 (31.1) | 3,473 (35.8) | |
| No surgery, chemo done, radiation done | 7,901 (32) | 3,050 (31.4) | |
| Surgery done, no chemo, no radiation | 856 (3.5) | 116 (1.2) | |
| Surgery done, no chemo, radiation done | 64 (0.3) | 8 (0.1) | |
| Surgery done, chemo done, no radiation | 1,000 (4.1) | 165 (1.7) | |
| Surgery done, chemo done, radiation done | 936 (3.8) | 155 (1.6) | |
| Primary site | <0.001 | ||
| C340 | 2,298 (9.3) | 911 (9.4) | |
| C341 | 11,019 (44.6) | 4,152 (42.8) | |
| C342 | 968 (3.9) | 368 (3.8) | |
| C343 | 4,959 (20.1) | 1,923 (19.8) | |
| C348 | 485 (2) | 200 (2.1) | |
| C349 | 4,951 (20.1) | 2,146 (22.1) | |
| Laterality | <0.001 | ||
| Not a paired site | 2,298 (9.3) | 911 (9.4) | |
| Only one side involved | 20,447 (82.8) | 8,016 (82.6) | |
| Bilateral involvement | 624 (2.5) | 154 (1.6) | |
| Paired site but lateral origin unknown; midline tumor | 1,311 (5.3) | 619 (6.4) | |
| Grade | <0.001 | ||
| Well differentiated | 88 (0.4) | 8 (0.1) | |
| Moderately differentiated | 179 (0.7) | 39 (0.4) | |
| Poorly differentiated | 2,795 (11.3) | 899 (9.3) | |
| Undifferentiated | 5,037 (20.4) | 1,457 (15) | |
| Cell type not determined, not stated or not applicable | 16,581 (67.2) | 7,297 (75.2) | |