Changing patterns of colorectal cancer in China over a period of 20 years

Table 1 Epidemiologic results

	1980s (%)	1990s (%)	P
Total number of CRCs	3420	6781
Male	2 053 (60.03)	3780 (55.74)
Female	1 367 (39.97)	3001 (44.26)
Male/female ratio	1.50:1	1.26:1	0.02
Mean age (yr)	56.83	59.66

Table 2 Distribution of CRC

Localization	1980s (%)	1990s (%)	P
Rectum	2 484 (72.6)	4 539 (66.9)	< 0.001
Colon	936 (27.4)	2 242 (33.1)	< 0.001
Distal
Sigmoid	337 (9.9)	844 (12.4)	< 0.001
Descending colon	226 (6.6)	366 (5.4)	0.02
Total distal CRCs	563 (16.5)	1 210 (17.85)
Proximal
Transverse colon	87 (2.5)	275 (4.1)	< 0.001
Ascending colon	286 (8.4)	757 (11.2)	< 0.001
Total proximal CRCs	373 (10.9)	1 032 (15.2)	< 0.001
Others
Total number of CRCs	3 420	6 781

Table 3 Dukes’ staging

Stage	1980s (%)	1990s (%)	P
A	306 (13.3)	416 (11)	0.01
B	679 (29.5)	1399 (37.1)	< 0.001
C	823 (35.8)	1379 (36.6)
D	492 (21.4)	578 (15.3)	< 0.001
Total	2 300	3772

Table 4 Pathologic classification

Pathologic classification	1980s (%)	1990s (%)	P
Adenocarcinoma	1251 (82.1)	3838 (85.6)	< 0.001
Mucinous adenocarcinoma	231 (15.2)	465 (10.4)	< 0.001
Others	42 (2.8)	180 (4)
Total	1524	4483