Table 1. Demographic and tumor baseline characteristics of the 3 groups before and after PSM.
| Clinicopathological variables | Unweighted result, n (%) | PSM result, n (%) | |||||||
|---|---|---|---|---|---|---|---|---|---|
| R-CC | L-CC | ReC | P | R-CC | L-CC | ReC | P | ||
| Total | 36,164 (49.3) | 20,266 (27.6) | 16,920 (23.1) | 8,670.00 | 8,670.00 | 8,670.00 | |||
| Age, years | <0.001 | 0.25 | |||||||
| <60 | 8,017 (22.2) | 7,720 (38.1) | 7,527 (44.5) | 1,612 (18.6) | 3,624 (41.8) | 4,136 (47.7) | |||
| ≥60 | 28,147 (77.8) | 12,546 (61.9) | 9,393 (55.5) | 7,058 (81.4) | 5,046 (58.2) | 4,534 (52.3) | |||
| Sex | <0.001 | 0.18 | |||||||
| Male | 16,986 (47.0) | 11,029 (54.4) | 10,025 (59.2) | 4,188 (48.3) | 4,517 (52.1) | 5,089 (58.7) | |||
| Female | 19,178 (53.0) | 9,237 (45.6) | 6,895 (40.8) | 4,482 (51.7) | 4,153 (47.9) | 3,581 (41.3) | |||
| Year of diagnosis | 0.11 | 0.96 | |||||||
| 2010–2012 | 17,818 (49.3) | 10,209 (50.4) | 8,257 (48.8) | 4,370 (50.4) | 4,439 (51.2) | 4,309 (49.7) | |||
| 2013–2015 | 18,346 (50.7) | 10,057 (49.6) | 8,663 (51.2) | 4,300 (49.6) | 4,231 (48.8) | 4,361 (50.3) | |||
| Histologic type | <0.001 | <0.001 | |||||||
| Adenocarcinomas | 30,965 (85.6) | 18,806 (92.8) | 15,875 (93.8) | 7,213 (83.2) | 7,864 (90.7) | 7,985 (92.1) | |||
| Non-adenocarinomas | 5,199 (14.4) | 1,460 (7.2) | 1,045 (6.2) | 1,457 (16.8) | 806 (9.3) | 685 (7.9) | |||
| Grade | <0.001 | 0.08 | |||||||
| Grade I | 2,463 (6.8) | 1,489 (7.3) | 1,124 (6.6) | 511 (5.9) | 599 (6.9) | 546 (6.3) | |||
| Grade II | 24,373 (67.4) | 15,682 (77.4) | 13,362 (79.0) | 6,008 (69.3) | 6,658 (76.8) | 6,745 (77.8) | |||
| Grade III | 7,590 (21.0) | 2,605 (12.9) | 2,089 (12.3) | 2,037 (23.5) | 980 (11.3) | 997 (11.5) | |||
| Grade IV | 1,738 (4.8) | 490 (2.4) | 345 (2.0) | 114 (1.3) | 433 (5.0) | 382 (4.4) | |||
| AJCC 6th ed | <0.001 | 0.07 | |||||||
| I | 6,698 (18.5) | 3,558 (17.6) | 3,136 (18.5) | 1,518 (17.5) | 1,326 (15.3) | 1,491 (17.2) | |||
| II | 12,555 (34.7) | 6,102 (30.1) | 4,652 (27.5) | 3,190 (36.8) | 2,462 (28.4) | 2,124 (24.5) | |||
| III | 11,530 (31.9) | 7,154 (35.3) | 7,188 (42.5) | 2,662 (30.7) | 3,286 (37.9) | 3,867 (44.6) | |||
| IV | 5,381 (14.9) | 3,452 (17.0) | 1,944 (11.5) | 1,300 (15.0) | 1,596 (18.4) | 1,188 (13.7) | |||
| T-stage | <0.001 | <0.001 | |||||||
| T1 | 2,699 (7.5) | 1,846 (9.1) | 1,476 (8.7) | 598 (6.9) | 988 (11.4) | 590 (6.8) | |||
| T2 | 5,424 (15.0) | 2,769 (13.7) | 2,861 (16.9) | 1,231 (14.2) | 1,379 (15.9) | 1,743 (20.1) | |||
| T3 | 20,827 (57.6) | 11,646 (57.5) | 10,514 (62.1) | 5,531 (63.8) | 4,681 (54.0) | 5,020 (57.9) | |||
| T4 | 7,214 (19.9) | 4,005 (19.8) | 2,069 (12.2) | 1,310 (15.1) | 1,622 (18.7) | 1,317 (15.2) | |||
| N-stage | <0.001 | <0.001 | |||||||
| N0 | 20,085 (55.5) | 10,346 (51.1) | 8,168 (48.3) | 5,124 (59.1) | 4,170 (48.1) | 4,578 (52.8) | |||
| N1 | 9,200 (25.4) | 6,196 (30.6) | 5,771 (34.1) | 1,726 (19.9) | 2,818 (32.5) | 2,592 (29.9) | |||
| N2 | 6,879 (19.0) | 3,724 (18.4) | 2,981 (17.6) | 1,820 (21.0) | 1,682 (19.4) | 1,500 (17.3) | |||
| M-stage | <0.001 | <0.001 | |||||||
| M0 | 30,783 (85.1) | 16,814 (83.0) | 14,976 (88.5) | 7,638 (88.1) | 7,023 (81.0) | 7,725 (89.1) | |||
| M1 | 5,381 (14.9) | 3,452 (17.0) | 1,944 (11.5) | 1,032 (11.9) | 1,647 (19.0) | 945 (10.9) | |||
| Combined diagnosis-liver | 0.34 | 0.05 | |||||||
| Yes | 3,553 (9.8) | 2,591 (12.8) | 1,393 (8.2) | 754 (8.7) | 1,162 (13.4) | 806 (9.3) | |||
| No | 32,611 (90.2) | 17,675 (87.2) | 15,527 (91.8) | 7,916 (91.3) | 7,508 (86.6) | 7,864 (90.7) | |||
| Surg Oth Reg/Dis | <0.001 | 0.75 | |||||||
| Yes | 2,844 (7.9) | 1,812 (8.9) | 1,352 (8.0) | 533 (6.2) | 660 (7.7) | 815 (9.4) | |||
| No | 33,302 (92.1) | 18,444 (91.0) | 15,557 (91.9) | 8,132 (93.8) | 8,002 (92.3) | 7,846 (90.6) | |||
| Unknown | 18 (0.0) | 10 (0.0) | 11 (0.1) | 5 (0.0) | 8 (0.1) | 9 (0.1) | |||
| Primary tumor size | <0.001 | 0.69 | |||||||
| <5 cm | 19,276 (53.3) | 12,369 (61.0) | 10,089 (59.6) | 4,552 (52.5) | 5,497 (63.4) | 5,297 (61.1) | |||
| ≥5 cm | 16,888 (46.7) | 7,897 (39.0) | 6,831 (40.4) | 4,118 (47.5) | 3,173 (36.6) | 3,373 (38.9) | |||
| Marital status | <0.001 | 0.04 | |||||||
| Married | 19,787 (54.7) | 11,711 (57.8) | 10,149 (60.0) | 4,500 (51.9) | 5,115 (59.0) | 5,367 (61.9) | |||
| Single | 5,117 (14.1) | 3,641 (18.0) | 2,897 (17.1) | 1,361 (15.7) | 1,587 (18.3) | 1,439 (16.6) | |||
| SDW | 11,260 (31.1) | 4,914 (24.2) | 3,874 (22.9) | 2,809 (32.4) | 1,968 (22.7) | 1,864 (21.5) | |||
| Radiation recode | <0.001 | 0.08 | |||||||
| Yes | 470 (1.3) | 624 (3.1) | 8,771 (51.8) | 78 (0.9) | 303 (3.5) | 4,430 (51.1) | |||
| No | 35,964 (98.7) | 19,642 (96.9) | 8,149 (48.2) | 8,592 (99.1) | 8,367 (96.5) | 4,240 (48.9) | |||
| Chemotherapy recode | <0.001 | 0.40 | |||||||
| Yes | 13,081 (36.2) | 9,268 (45.7) | 11,339 (67.0) | 3,026 (34.9) | 3,890 (44.9) | 5,982 (69.0) | |||
| No | 23,083 (63.8) | 10,998 (54.3) | 5,581 (33.0) | 5,644 (65.1) | 4,777 (55.1) | 2,688 (31.0) | |||
| LNR | <0.001 | <0.001 | |||||||
| <0.3 | 31,442 (86.9) | 17,557 (86.6) | 14,960 (88.4) | 7,560 (87.2) | 7,655 (88.3) | 7,716 (89.0) | |||
| ≥0.3 | 4,722 (13.1) | 2,709 (13.4) | 1,960 (11.6) | 1,110 (12.8) | 1,015 (11.7) | 954 (11.0) | |||
| CEA level | <0.001 | 0.13 | |||||||
| Positive | 15,041 (41.6) | 8,932 (44.1) | 7,275 (43.0) | 3,546 (40.9) | 4,023 (46.4) | 3,884 (44.8) | |||
| Negative | 21,123 (58.4) | 11,334 (55.9) | 9,645 (57.0) | 5,124 (59.1) | 4,647 (53.6) | 4,786 (55.2) | |||
The data in brackets represent the number of this item accounts for the total number of clinicopathological variables in a kind of colorectal cancer. For example, 22.2% is the number of patients whose age <60 (8,017) accounts for total number of R-CC (36,164). PSM, propensity score matching; R-CC, right-sided colon cancer; L-CC, left-sided colon cancer; ReC, rectal cancer; AJCC, American Joint Committee on Cancer; Combined diagnosis -liver, with liver metastasis; Surg Oth Reg/Dis, having surgical operation on metastatic foci; SDW, separated, divorced and widowed; LNR, lymph node ratio; CEA, carcinoembryonic antigen.