Equipping the American Joint Committee on Cancer Staging for Resectable Pancreatic Ductal Adenocarcinoma with Tumor Grade: A Novel Staging System

Table 1

Baseline clinicopathologic characteristics.

Characteristics	Training set (n = 4983) (%)	Internal validation set (n = 4983) (%)	External validation set (n = 324) (%)
Age, yrs
<65	2172 (43.6)	2185 (43.8)	212 (65.4)
≥65	2811 (56.4)	2798 (56.2)	112 (34.6)
Sex
Male	2461 (49.4)	2478 (49.7)	136 (42.0)
Female	2522 (50.6)	2505 (50.3)	188 (58.0)
Location
Head	3832 (76.8)	3842 (77.1)	161 (49.7)
Body and tail	704 (14.2)	717 (14.4)	163 (50.3)
Other	447 (9.0)	424 (8.5)	0 (0)
Year of diagnosis
2004–2009	2049 (41.1)	2010 (40.3)	—
2010–2015	2934 (58.9)	2973 (59.7)	—
Grade
Low grade	3063 (61.5)	3115 (62.5)	165 (50.9)
High grade	1920 (38.5)	1868 (37.5)	159 (49.1)
Examined lymph nodes
<15	2187 (46.1)	2221 (46.6)	183 (56.5)
≥15	2558 (53.9)	2547 (53.4)	141 (43.5)
7th AJCC stage
IA	188 (3.8)	192 (3.9)	7 (2.2)
IB	270 (5.4)	292 (5.9)	36 (11.1)
IIA	1105 (22.2)	1081 (21.7)	130 (40.1)
IIB	3418 (68.6)	3417 (68.5)	151 (46.6)
8th T stage
T1	833 (16.7)	801 (16.1)	44 (13.5)
T2	2928 (58.8)	3023 (60.7)	179 (54.9)
T3	1222 (24.5)	1159 (23.3)	103 (31.6)
8th N stage
N0	1610 (32.3)	1591 (31.9)	180 (55.2)
N1	2084 (41.8)	2114 (42.4)	112 (34.4)
N2	1289 (25.9)	1278 (25.6)	34 (10.4)
Extrapancreatic invasion 8th AJCC stage	4106 (82.4)	4100 (82.3)	250 (76.7)
IA	393 (7.9)	379 (7.6)	24 (7.4)
IB	886 (17.8)	885 (17.8)	97 (29.9)
IIA	331 (6.6)	327 (6.6)	58 (17.9)
IIB	2084 (41.8)	2114 (42.4)	111 (34.3)
III	1289 (25.9)	1278 (25.6)	34 (10.5)
Median OS (95% CI)	19 (18.4–19.6)	19.0 (18.4–19.6)	23.6 (19.4–27.8)

Values in parentheses are percentages.