Table 1.

Demographics and clinicopathological characteristics. Categorical variables are presented as n (%) and continuous variables as median (interquartile range).

	Total (3,726)	East (3,166)	West (560)	p
Age, years	63 (54–71)	62 (54–70)	68 (59–75)	< 0.001
Female	1,273 (34.2)	1,006 (31.8)	267 (47.7)	< 0.001
Race				< 0.001
White	302 (8.1)	0 (0.0)	302 (53.9)
Asian	3,210 (86.2)	3,166 (100)	44 (7.9)
Black	23 (0.6)	0	23 (4.1)
Other or unknown	191 (5.1)	0	191 (34.1)
Year of surgery	2011 (2007–2015)	2011 (2007–2015)	2010 (2001–2014)	< 0.001
Location				0.023
Proximal third	516 (13.8)	452 (14.3)	64 (11.4)
Middle third	1,245 (33.4)	1,062 (33.5)	183 (32.7)
Distal third	1,907 (51.2)	1,597 (50.4)	310 (55.4)
Multiple/diffuse	58 (1.6)	55 (1.7)	3 (0.5)
Type of surgery				0.011
Distal	2,818 (75.6)	2,374 (75.0)	444 (79.3)
Total	825 (22.1)	726 (22.9)	99 (17.7)
Proximal	83	66 (2.1)	17 (3.0)
pN positive	854 (22.9)	701 (22.1)	153 (27.3)	0.007
pN status				0.02
0	2,872 (77.1)	2,465 (77.9)	407 (72.7)
1	535 (14.4)	440 (13.9)	95 (17.0)
2	225 (6.0)	186 (5.9)	39 (7.0)
3a	83 30	64 (2.0)	19 (3.4)
3b	11 (0.3)	11 (0.3)	0 (0.0)
Dissected nodes	34 (25–45)	36 (27–46)	22 (15–32)	< 0.001
Positive nodes	0 (0–0)	0 (0–0)	0 (0–1)	0.008
Tumor size, mm	25 (18–40)	25 (18–40)	25 (15–35)	0.002
Differentiation				0.002
Well	598 (16.0)	539 (17.0)	59 (10.5)
Moderate	1,470 (39.5)	1,236 (39.0)	234 (41.8)
Poor	1,454 (39.0)	1,220 (38.5)	234 (41.8)
Unknown	204 (5.5)	171 (5.4)	33 (5.9)
Signet histology	626 (16.8)	527 (16.6)	99 (17.7)	< 0.001
Unknown	455 (12.2)	237 (7.5)	218 (38.9)
Lymphovascular invasion	705 (18.9)	600 (19.0)	105 (18.8)	< 0.001
Unknown	299 (8.0)	39 (1.2)	260 (46.4)