Table 1. Characteristics of Patients from SEER Database by age.
| Total | Young Group | Elderly Group | P value | |
| Characteristic | (n = 69835) | (n = 3014) | (n = 66821) | |
| Media foullow up(mo) | 112 | 98 | P<0.001 | |
| (IQR) | 58–158 | 42–135 | ||
| Years of diagnosis | P<0.001 | |||
| 1988–1993 | 16017 | 609 | 15408 | |
| 1994–1999 | 21295 | 955 | 20340 | |
| 2000–2003 | 32523 | 1450 | 31073 | |
| Sex | 0.615 | |||
| male | 37130 | 1589 | 35541 | |
| female | 32705 | 1425 | 31280 | |
| Race | P<0.001 | |||
| Caucasian | 55824 | 2183 | 53641 | |
| African American | 7390 | 431 | 6954 | |
| Others | 6443 | 391 | 6052 | |
| Unknowns | 178 | 9 | 169 | |
| Primary site | 0.434 | |||
| Colon cancer | 51372 | 2236 | 49136 | |
| Rectal cancer | 18463 | 778 | 17685 | |
| Pathological grading | P<0.001 | |||
| High/Moderate | 54812 | 2167 | 52645 | |
| Poor/undifferentiation | 12644 | 723 | 11921 | |
| Histological Type | P<0.001 | |||
| Adenocarcinoma | 61384 | 2455 | 58929 | |
| Mucinous cancer | 7804 | 474 | 7330 | |
| Signet-ring cancer | 647 | 85 | 562 | |
| AJCC stage | P<0.001 | |||
| I | 4563 | 133 | 4430 | |
| II | 35867 | 1384 | 34483 | |
| III | 29405 | 1497 | 27908 | |
| No. of LNs dissected | P<0.001 | |||
| <12 | 37653 | 1037 | 36616 | |
| ≥12 | 32182 | 1977 | 30205 | |
| Metastasis LNR | P<0.001 | |||
| rN0(0) | 40546 | 1521 | 39025 | |
| rN1(0.01–0.20) | 12814 | 722 | 12092 | |
| rN2(0.21–0.60) | 11482 | 541 | 10941 | |
| rN3(>0.60) | 4993 | 230 | 4763 |