Clinicopathological characteristics and prognosis of gastric signet ring cell carcinoma

Table 1 General characteristics of Surveillance, Epidemiology and End Results and validation data sets

Variable	SEER data set (%), n = 5200	Validation data set (%), n = 603
Age (yr)
< 40	200 (3.85)	41 (6.80)
40-60	1389 (26.71)	313 (51.91)
60-80	2690 (51.73)	236 (39.14)
> 80	921 (17.71)	13 (2.15)
Sex
Male	2933 (56.40)	423 (70.15)
Female	2267 (43.60)	180 (29.85)
Race
White	2947 (56.67)
Black	830 (15.96)
Black-AI	52 (1.00)
Black-API	1371 (26.37)
T stage
T1a	597 (11.48)	247 (40.96)
T1b	708 (13.62)
T2	693 (13.33)	70 (11.61)
T3	1697 (32.63)	8 (1.33)
T4a	1155 (22.21)	278 (46.10)
T4b	350 (6.73)
N stage
N0	2233 (42.94)	266 (44.11)
N1	951 (18.29)	184 (30.52)
N2	855 (16.44)	89 (14.76)
N3	1161 (22.33)	64 (10.61)
AJCC stage
I	1580 (30.38)	262 (43.45)
II	1449 (27.87)	71 (11.77)
III	2171 (41.75)	270 (44.78)
Radiotherapy
Yes	1416 (27.23)	16 (2.66)
No	3784 (72.77)	587 (97.34)
Chemotherapy
Yes	2599 (49.98)	445 (73.80)
No	2601 (50.02)	158 (26.20)
Tumor size (cm)
< 2	820 (15.77)
2-5	2198 (42.27)	94 (15.59)
> 5	1700 (32.69)	393 (65.17)
NA	482 (9.27)	116 (19.24)
Histology
SRC	1326 (25.50)	84 (13.93)
Differentiated	1550 (29.81)	241 (39.97)
Undifferentiated	2324 (44.69)	278 (46.10)

SEER: Surveillance, Epidemiology and End Results; SRC: Signet ring cell carcinoma; API: Asian Pacific Islanders; AI: American Indians.

Table 2 Comparison of general characteristics of patients with different differentiated types of gastric cancer

Variable	Differentiated (%), n = 1550	P value	SRC (%), n = 1326	P value	Undifferentiated (%), n = 2324
Age (yr)
< 40	13 (0.84)	< 0.001	110 (8.30)	< 0.001	77 (3.31)
40-60	241 (15.55)	< 0.001	518 (39.06)	< 0.001	630 (27.11)
60-80	920 (59.35)	< 0.001	583 (43.97)	< 0.001	1187 (51.08)
> 80	376 (24.26)	< 0.001	115 (8.67)	< 0.001	430 (18.50)
Sex		< 0.001		< 0.001
Male	959 (61.87)		625 (47.13)		1349 (58.05)
Female	591 (38.13)		701 (52.87)		975 (41.95)
Race
White	804 (51.87)	< 0.001	819 (61.74)	0.005	1324 (56.97)
Black	295 (19.03)	0.001	188 (14.19)	0.536	347 (14.93)
Black-AI	16 (1.03)	0.890	13 (0.98)	0.978	23 (0.99)
Black-API	435 (28.07)	0.002	306 (23.09)	0.007	630 (27.11)
T stage
T1a	281 (18.13)	0.004	187 (14.10)	< 0.001	129 (5.56)
T1b	325 (20.97)	< 0.001	126 (9.51)	0.140	257 (11.06)
T2	242 (15.61)	0.002	155 (11.69)	0.355	296 (12.74)
T3	450 (29.03)	0.930	383 (28.89)	< 0.001	864 (37.17)
T4a	171 (11.03)	< 0.001	385 (29.03)	0.033	599 (25.77)
T4b	81 (5.23)	0.078	90 (6.78)	0.309	179 (7.70)
N stage
N0	946 (61.03)	< 0.001	512 (38.61)	0.001	775 (33.35)
N1	278 (17.94)	0.097	207 (15.61)	0.001	466 (20.05)
N2	181 (11.68)	0.010	198 (14.93)	< 0.001	476 (20.48)
N3	145 (9.35)	< 0.001	409 (30.85)	0.002	607 (26.12)
AJCC stage
I	730 (47.10)	< 0.001	372 (28.05)	< 0.001	478 (20.57)
II	452 (29.16)	< 0.001	305 (23.00)	< 0.001	692 (29.78)
III	368 (23.74)	< 0.001	649 (48.95)	0.679	1154 (49.65)
Primary site
Fundus	67 (4.32)	0.084	41 (3.09)	0.665	78 (3.36)
Body	198 (12.77)	0.527	180 (13.58)	0.898	319 (13.73)
Antrum	640 (41.29)	< 0.001	434 (32.73)	0.061	832 (35.80)
Pylorus	85 (5.48)	0.879	71 (5.36)	0.687	132 (5.68)
Lesser curve	228 (14.71)	0.694	202 (15.23)	0.452	376 (16.18)
Lesser curve-Greater curve	85 (5.48)	0.294	85 (6.41)	0.218	126 (5.42)
Lesser curve-Overlapping/NOS	247 (15.95)	< 0.001	313 (23.60)	0.007	461 (19.83)
Radiotherapy		< 0.001		0.410
Yes	304 (19.61)		415 (31.30)		697 (29.99)
No	1246 (80.39)		911 (68.70)		1627 (70.01)
Chemotherapy		< 0.001		0.015
Yes	535 (34.52)		785 (59.20)		1279 (55.03)
No	1015 (65.48)		541 (40.80)		1045 (44.97)
Tumor size (cm)
< 2	354 (22.84)	< 0.001	212 (15.99)	< 0.001	254 (10.93)
2-5	674 (43.48)	0.008	512 (38.61)	0.004	1012 (43.55)
> 5	420 (27.10)	0.017	413 (31.15)	< 0.001	867 (37.31)
NA	102 (6.58)	< 0.001	189 (14.25)	< 0.001	191 (8.21)

SRC: Signet ring cell carcinoma; API: Asian Pacific Islanders; AI: American Indians.

Table 3 Analysis of survival and prognosis of patients with early gastric cancer

Variable	OS (EGC = 1305) or (95%CI)	P value	OS (SRC = 313) or (95%CI)	P value
Age (yr)		< 0.001		0.128
< 40	1 (Reference)		1 (Reference)
40-60	1.189 (0.282-5.015)	0.813	1.071 (0.128-8.947)	0.950
60-80	2.246 (0.550-9.174)	0.260	2.072 (0.268-16.012)	0.485
> 80	5.516 (1.337-22.753)	0.018	4.204 (0.463-38.177)	0.202
Race		< 0.001		0.093
White	1 (Reference)		1 (Reference)
Black	1.459 (1.053-2.022)	0.023	2.052 (0.878-4.793)	0.097
Black-AI	1.947 (0.476-7.960)	0.354	0.000	0.990
Black-API	0.497 (0.358-0.691)	< 0.001	0.471 (0.137-1.271)	0.124
Sex
Male	1 (Reference)		1 (Reference)
Female	0.610 (0.467-0.797)	< 0.001	0.791 (0.383-1.632)	0.526
Tumor size (cm)		0.057		0.700
< 2	1 (Reference)		1 (Reference)
2-5	1.317 (0.982-1.764)	0.066	1.579 (0.707-3.525)	0.265
> 5	1.859 (1.161-2.978)	0.010	0.000	0.974
AJCC stage
I	1 (Reference)		1 (Reference)
II	1.836 (1.100-3.064)	0.020	0.965 (0.231-4.027)	0.961
Depth
T1a	1 (Reference)		1 (Reference)
T1b	1.280 (0.962-1.703)	0.090	1.786 (0.810-3.938)	0.151
LNM1
N0	1 (Reference)		1 (Reference)
N1-3	1.271 (0.859-1.880)	0.230	2.134 (0.883-5.154)	0.151
Histology		0.045
Differentiated	1(Reference)
SRC	0.636 (0.426-0.950)	0.027
Undifferentiated	1.039 (0.780-1.384)	0.794
SRC vs non-SRC	0.626 (0.427-0.919)	0.017

¹LNM: Lymph node metastasis.

OS: Overall survival; SRC: Signet ring cell carcinoma; EGC: Early gastric cancer; API: Asian Pacific Islanders; AI: American Indians.

Table 4 Analysis of survival and prognosis of patients with advanced gastric cancer

Variable	OS (AGC = 3895), or (95%CI)	P value	OS (SRC = 1013), or (95%CI)	P value
Age (yr)		< 0.001		< 0.001
< 40	1 (Reference)		1 (Reference)
40-60	1.130 (0.882-1.447)	0.333	1.267 (0.898-1.788)	0.178
60-80	1.543 (1.212-1.985)	< 0.001	1.578 (1.123-2.218)	0.009
> 80	2.936 (2.281-3.780)	< 0.001	2.290 (1.528-3.431)	< 0.001
Race		< 0.001		< 0.001
White	1 (Reference)		1 (Reference)
Black	1.096 (0.973-1.234)	0.133	1.326 (1.057-1.663)	0.015
Black-AI	1.382 (0.949-2.015)	0.092	2.624 (1.423-4.838)	0.002
Black-API	0.726 (0.651-0.810)	< 0.001	0.800 (0.867-1.205)	0.041
Sex
Male	1 (Reference)		1(Reference)
Female	0.964 (0.883-1.052)	0.409	1.022 (0.867-1.205)	0.791
Tumor size (cm)		< 0.001		0.001
< 2	1 (Reference)		1 (Reference)
2-5	1.026 (0.823-1.280)	0.817	1.031 (0.680-1.565)	0.885
> 5	1.211 (0.971-1.511)	0.089	1.415 (0.930-2.152)	0.105
AJCC stage		0.019		0.028
I	1 (Reference)		1 (Reference)
II	1.227 (0.903-1.667)	0.191	1.946 (0.923-4.102)	0.080
III	1.584 (1.076-2.330)	0.020	3.050 (1.247-7.458)	0.015
T stage		< 0.001		< 0.001
T2	1 (Reference)		1 (Reference)
T3	1.384 (1.135-1.689)	0.001	1.857 (1.189-2.899)	0.006
T4	2.025 (1.633-2.512)	< 0.001	2.615 (1.644-4.161)	< 0.001
N stage		< 0.001		0.086
N0	1 (Reference)		1 (Reference)
N1	1.241 (1.056-1.459)	0.009	1.061 (0.744-1.512)	0.745
N2	1.295 (1.050-1.597)	0.016	1.034 (0.665-1.608)	0.881
N3	1.904 (1.549-2.341)	< 0.001	1.341 (0.882-2.037)	0.170
Histology		0.002
Differentiated	1 (Reference)
SRC	1.276 (1.117-1.458)	< 0.001
Undifferentiated	1.164 (1.037-1.306)	0.010
SRC vs non-SRC	1.139 (1.030-1.258)	0.011
Adjuvant therapy				< 0.001
Radiotherapy			0.635 (0.367-1.099)	0.105
Chemotherapy			0.481 (0.388-0.595)	< 0.001
Radiotherapy + Chemotherapy			0.414 (0.334-0.512)	< 0.001
None			1 (Reference)

OS: Overall survival; SRC: Signet ring cell carcinoma; AGC: Advanced gastric cancer; API: Asian Pacific Islanders; AI: American Indians.

Table 5 Scores of risk factors in the survival prognosis model of advanced gastric signet ring cell carcinoma

Variable	Points	Total points	3/5-yr survival	Total points
Age (yr)		0-56	0.9-1	0-33
< 40	0	56-111	0.8-0.9	33-88
40-60	18	111-146	0.7-0.8	33-123
60-80	36	146-172	0.6-0.7	123-149
> 80	60	172-195	0.5-0.6	149-172
Race		195-215	0.4-0.5	172-192
White	15	215-235	0.3-0.4	192-212
Black	37	235-257	0.2-0.3	212-234
Black-AI	92	257-283	0.1-0.2	234-260
Black-API	0	> 283	< 0.1	> 260
Tumor size (cm)
< 2	0
2-5	5
> 5	31
NA	42
AJCC stage
I	0
II	54
III	100
T stage
T2	0
T3	41
T4	67
Adjuvant therapy
Radiotherapy	33
Chemotherapy	10
Radiotherapy + Chemotherapy	0
None	67

API: Asian Pacific Islanders; AI: American Indians.