Nomogram for overall survival in ampullary adenocarcinoma using the surveillance, epidemiology, and end results database and external validation

Table 1 Patient baseline characteristics, n (%)

Characteristics	Training cohort (n = 1406)	Internal validation cohort (n = 603)	External validation cohort (n = 257)
Age
< 50	109 (7.8)	56 (9.3)	24 (9.3)
50-59	267 (19.0)	127 (21.1)	80 (31.1)
60-69	381 (27.1)	153 (25.4)	78 (30.4)
70-79	358 (25.5)	172 (28.5)	61 (23.7)
≥ 80	291 (20.7)	95 (15.8)	14 (5.4)
Sex
Female	626 (44.5)	274 (45.4)	110 (42.8)
Male	780 (55.5)	329 (54.6)	147 (57.2)
Race
White	1075 (76.5)	465 (77.1)	0 (0)
Black	107 (7.6)	53 (8.8)	0 (0)
Unknown	224 (15.9)	85 (14.1)	257 (100)
SEER stage
Localized	207 (14.7)	79 (13.1)	91 (35.4)
Regional	795 (56.5)	371 (61.5)	57 (22.2)
Distant	357 (25.4)	130 (21.6)	84 (32.7)
Unknown	47 (3.3)	23 (3.8)	25 (9.7)
Surgery
No	373 (26.5)	155 (25.7)	38 (14.8)
Surgical removal of primary site	412 (29.3)	201 (33.3)	154 (59.9)
Radical surgery	621 (44.2)	247 (41.0)	65 (25.3)
Radiation
No	1123 (79.8)	478 (79.3)	249 (96.9)
Yes	283 (20.1)	125 (20.7)	8 (3.1)
Chemotherapy
No	762 (54.2)	325 (53.9)	167 (65.0)
Yes	644 (45.8)	278 (46.1)	90 (35.0)
Bone metastasis
No	1404 (99.9)	598 (99.2)	254 (98.8)
Yes	2 (0.1)	5 (0.8)	3 (1.2)
Brain metastasis
No	1402 (99.7)	601 (99.7)	257 (100)
Yes	4 (0.3)	2 (0.3)	0 (0)
Liver metastasis
No	1309 (93.1)	557 (92.4)	226 (87.9)
Yes	97 (6.9)	46 (7.6)	31 (12.1)
Lung metastasis
No	1378 (98.0)	591 (98.0)	250 (97.3)
Yes	28 (2.0)	12 (2.0)	7 (2.7)
Tumor size
< 2 cm	452 (32.1)	185 (30.7)	82 (31.9)
> 2 cm	698 (49.6)	322 (53.4)	117 (45.5)
Unknown	256 (18.2)	96 (15.9)	58 (22.6)
LNR
0	468 (33.3)	198 (32.8)	175 (68.1)
0-0.5	468 (33.3)	220 (36.5)	14 (5.4)
0.5-1	61 (4.3)	20 (3.3)	25 (9.7)
Unknown	409 (29.1)	165 (27.4)	43 (16.7)
Marital status
Single	235 (16.7)	110 (18.2)	3 (1.2)
Divorced	127 (9.0)	48 (8.0)	6 (2.3)
Married	769 (54.7)	341 (56.6)	237 (92.2)
Widowed	220 (15.6)	71 (11.8)	11 (4.3)
Unknow	55 (3.9)	33 (5.5)	0 (0)
Stage T
T1	276 (19.6)	107 (17.7)	27 (10.5)
T2	366 (26.0)	171 (28.4)	96 (37.4)
T3	334 (23.8)	152 (25.2)	37 (14.4)
T4	351 (25.0)	140 (23.2)	57 (22.2)
Unknown	79 (5.6)	33 (5.5)	40 (15.6)
Stage N
N0	775 (55.1)	322 (53.4)	135 (52.5)
N1	583 (41.5)	264 (43.8)	50 (19.5)
Unknown	48 (3.4)	17 (2.8)	72 (28.0)
Stage M
M0	1251 (89.0)	543 (90.0)	223 (86.8)
M1	155 (11.0)	60 (10.0)	34 (13.2)
Extension
Localized	131 (9.3)	54 (9.0)	40 (15.6)
Duodenal wall	554 (39.4)	244 (40.5)	95 (40.0)
Pancreas	346 (24.6)	157 (26.0)	52 (20.2)
Common bile duct	88 (6.3)	43 (7.1)	27 (10.5)
Invasive tumor confined	208 (14.8)	72 (11.9)	33 (12.8)
Extension to other adjacent organs	79 (5.6)	33 (5.5)	10 (3.9)
Tumor differentiation
Well differentiated	138 (9.8)	65 (10.8)	20 (7.8)
Moderately differentiated	668 (47.5)	288 (47.8)	105 (40.9)
Poorly differentiated	377 (26.8)	160 (26.5)	77 (30.0)
Undifferentiated	16 (1.1)	2 (0.3)	27 (10.5)
Unknown	207 (14.7)	88 (14.6)	28 (10.9)

LNR: Lymph node ratio; SEER: Surveillance, epidemiology, and end results.