Table 1.
Analysis of the main characteristics of patients with rectal adenocarcinoma
| Variables | Overall N(%) |
Train cohort N(%) |
Test cohort N(%) |
P |
|---|---|---|---|---|
| Patients | 49,275 | 34,492(70.0%) | 14,783(30.0%) | |
| Sex | ||||
| Female | 19,771(40.1%) | 13,878(40.2%) | 5893(39.9%) | 0.440 |
| Male | 29,504(59.9%) | 20,614(59.8%) | 8890(60.1) | |
| Age at diagnosis | ||||
| mean ± sd | 62.6 ± 13.5 | 62.5 ± 13.5 | 62.7 ± 13.4 | 0.131 |
| Race | ||||
| Black | 4174(8.5%) | 2951(8.6%) | 1223(8.3%) | 0.326 |
| White | 40,063(81.3%) | 28,053(81.3%) | 12,010(81.2%) | |
| Amercian Indian/Alaska Native | 390(0.8%) | 279(0.8%) | 111(0.8%) | |
| Asian or Pacific Islander | 4648(9.4%) | 3209(9.3%) | 1439(9.7%) | |
| Marital status at diagnosis | ||||
| Married | 29,160(59.2%) | 20,482(59.4%) | 8678(58.7%) | 0.160 |
| Unmarried | 20,115(40.8%) | 14,010(40.6%) | 6105(41.3%) | |
| Histologic# | ||||
| PA | 36,549(74.2%) | 25,564(74.1%) | 10,985(74.3%) | 0.847 |
| TA | 10,364(21.0%) | 7285(21.1%) | 3079(20.8%) | |
| MA | 1955(4.0%) | 3143(3.9%) | 598(4.0%) | |
| SRCC | 407(0.8%) | 423(0.9%) | 121(0.9%) | |
| Grade | ||||
| Grade I | 4537(9.2%) | 3143(9.1%) | 1394(9.4%) | 0.717 |
| Grade II | 37,522(76.2%) | 26,298(76.3%) | 11,224(76.0%) | |
| Grade III | 6616(13.4%) | 4628(13.4%) | 1988(13.4%) | |
| Grade IV | 600(1.2%) | 423(1.2%) | 177(1.2%) | |
| AJCC | ||||
| I | 15,009(30.5%) | 10,501(30.5%) | 4508(30.5%) | 0.888 |
| II | 10,899(22.1%) | 7601(22.0%) | 3298(22.3%) | |
| III | 15,048(30.5%) | 10,546(30.6%) | 4502(30.5%) | |
| IV | 8319(16.9%) | 5844(16.9%) | 2475(16.7%) | |
| T | ||||
| T0 | 7(0.01%) | 5(0.01%) | 2(0.01%) | 0.616 |
| T1 | 10,071(20.4%) | 7071(20.5%) | 3000(20.3%) | |
| T2 | 7940(16.1%) | 5502(16.0%) | 2438(16.5%) | |
| T3 | 23,928(48.6%) | 16,786(48.7%) | 7142(48.3%) | |
| T4 | 4089(8.3%) | 2832(8.2%) | 1257(8.5%) | |
| TX | 2111(4.3%) | 1494(4.3%) | 617(4.2%) | |
| Tis | 1123(2.3%) | 796(2.3%) | 327(2.2%) | |
| N | ||||
| N0 | 28,582(58.0%) | 19,965(57.9%) | 8617(58.3%) | 0.765 |
| N1 | 13,613(27.6%) | 9577(27.8%) | 4036(27.3%) | |
| N2 | 5936(12.1%) | 4148(12.0%) | 1788(12.1%) | |
| NX | 1144(2.3%) | 802(2.3%) | 342(2.3%) | |
| M | 0 | |||
| M0 | 40,934(83.1%) | 28,633(83.0%) | 12,301(83.2%) | 0.848 |
| M1 | 8319(16.9%) | 5844(16.9%) | 2475(16.7%) | |
| MX | 22(0.05%) | 15(0.1%) | 7(0.1%) | |
| Summary stage | 0 | |||
| Regional | 20,563(41.7%) | 14,358(41.6%) | 6205(42.0%) | 0.755 |
| Distant | 19,956(40.5%) | 13,986(40.5%) | 5970(40.4%) | |
| Localized | 8756(17.8%) | 6148(17.9%) | 2608(17.6%) | |
| Surgery performed | 0 | |||
| No | 8367(17.0%) | 5877(17.0%) | 2490(16.8%) | 0.597 |
| Yes | 40,908(83.0%) | 28,615(83.0%) | 12,293(83.2%) | |
| Radiotherapy | 0 | |||
| No/Unknown | 21,408(43.4%) | 15,019(43.5%) | 6389(43.2%) | 0.505 |
| Yes | 27,867(56.6%) | 19,473(56.5%) | 8394(56.8%) | |
| Chemotherapy | 0 | |||
| No/Unknown | 18,286(37.1%) | 12,836(37.2%) | 5450(36.9%) | 0.464 |
| Yes | 30,989(63.1%) | 21,656(62.8%) | 9333(63.1%) | |
| Status | 0 | |||
| Death | 14,078(28.5%) | 9871(28.5%) | 4207(28.5%) | 0.790 |
| Alive | 35,247(71.5%) | 24,671(71.5%) | 10,576(71.5%) | |
#PA Papillary adenocarcinoma, morphology code 8140; TA Tubular adenocarcinoma, morphology code 8210–8221, 8261–8263; MA Mucinous adenocarcinomas, morphology code 8480; SRCC Signet ring cell carcinoma, morphology code 8490