Adenosquamous carcinoma may have an inferior prognosis to signet ring cell carcinoma in patients with stages I and II gastric cancer

Table 1 Patient characteristics dichotomized by histological type before propensity score matching, n (%)

Characteristic	SRC	ASC	Total	P value
	n = 5968 (98.4)	n = 95 (1.6)	n = 6063 (100)
Age (yr)				0.008
≤ 60	2823 (47.3)	32 (33.7)	2855 (47.1)
> 60	3145 (52.7)	63 (66.3)	3208 (52.9)
Gender				< 0.001
Male	3146 (52.7)	71 (74.7)	3217 (53.1)
Female	2822 (47.3)	24 (25.3)	2846 (46.9)
Race				0.045
White	4147 (69.5)	74 (77.9)	4221 (69.6)
Black	725 (12.1)	13 (13.7)	738 (12.2)
Others	1096 (18.4)	8 (8.4)	1104 (18.2)
Marital status				0.001
Not married	2287 (38.3)	21 (22.1)	2308 (38.1)
Married	3681 (61.7)	74 (77.9)	3755 (61.9)
Tumor size (mm)				0.220
≤ 50	2271 (38.1)	42 (44.2)	2313 (38.1)
> 50	3697 (61.9)	53 (55.8)	3750 (61.9)
TNM Stage				0.299
I	1595 (26.7)	21 (22.1)	1616 (26.7)
II	888 (14.9)	20 (21.1)	908 (15.0)
III	1129 (18.9)	15 (15.8)	1144 (18.9)
IV	2356 (39.5)	39 (41.1)	2395 (39.5)
Tumor depth				0.139
T1	1398 (23.4)	16 (16.8)	1414 (23.3)
T2	2177 (36.5)	45 (47.4)	2222 (36.6)
T3	1384 (23.2)	18 (18.9)	1402 (23.1)
T4	1009 (16.9)	16 (16.8)	1025 (16.9)
LN metastasis				0.011
N0	2472 (41.4)	31 (32.6)	2503 (41.3)
N1	2080 (34.9)	46 (48.4)	2126 (35.1)
N2	926 (15.5)	16 (16.8)	942 (15.5)
N3	490 (8.2)	2 (2.1)	492 (8.1)
Distant metastasis				0.966
No	4197 (70.3)	67 (70.5)	4264 (70.3)
Yes	1771 (29.7)	28 (29.5)	1799 (29.7)
Radiotherapy				0.006
No	4553 (76.3)	61 (64.2)	4614 (76.1)
Yes	1415 (23.7)	34 (35.8)	1449 (23.9)
Surgery				0.231
No	2047 (34.3)	27 (28.4)	2074 (34.2)
Yes	3921 (65.7)	68 (71.6)	3989 (65.8)

SRC: Signet ring cell carcinoma; ASC: Adenosquamous carcinoma; TNM: Tumor-node-metastasis; LN: Lymph node.

Table 2 Patient characteristics dichotomized by histological type after propensity score matching, n (%)

Characteristic	SRC	ASC	Total	P value
	n = 370 (79.6)	n = 95 (20.4)	n = 465 (100)
Age (yr)				0.754
≤ 60	131 (35.4)	32 (33.7)	163 (35.1)
> 60	239 (64.6)	63 (66.3)	302 (64.9)
Gender				0.809
Male	272 (73.5)	71 (74.7)	343 (73.8)
Female	98 (26.5)	24 (25.3)	122 (26.2)
Race				0.845
White	290 (78.4)	74 (77.9)	364 (78.3)
Black	44 (11.9)	13 (13.7)	57 (12.3)
Others	36 (9.7)	8 (8.4)	44 (9.5)
Marital status				0.901
Not married	84 (22.7)	21 (22.1)	105 (22.6)
Married	286 (77.3)	74 (77.9)	360 (77.4)
Tumor size (mm)				0.828
≤ 50	159 (43.0)	42 (44.2)	201 (43.2)
> 50	211 (57.0)	53 (55.8)	264 (56.8)
Stage				0.365
I	94 (25.4)	21 (22.1)	115 (24.7)
II	55 (14.9)	20 (21.1)	75 (16.1)
III	77 (20.8)	15 (15.8)	92 (19.8)
IV	144 (38.9)	39 (41.1)	183 (39.4)
Tumor depth				0.598
T1	77 (20.8)	16 (16.8)	93 (20.0)
T2	156 (42.2)	45 (47.4)	201 (43.2)
T3	84 (22.7)	18 (18.9)	102 (21.9)
T4	53 (14.3)	16 (16.8)	69 (14.8)
LN metastasis				0.151
N0	151 (40.8)	31 (32.6)	182 (39.1)
N1	134 (36.2)	46 (48.4)	180 (38.7)
N2	69 (18.6)	16 (16.8)	85 (18.3)
N3	16 (4.3)	2 (2.1)	18 (3.9)
Distant metastasis				0.840
No	257 (69.5)	67 (70.5)	324 (69.7)
Yes	113 (30.5)	28 (29.5)	141 (30.3)
Radiotherapy				0.786
No	232 (62.7)	61 (64.2)	293 (63.0)
Yes	138 (37.3)	34 (35.8)	172 (37.0)
Surgery				0.883
No	108 (29.2)	27 (28.4)	135 (29.0)
Yes	262 (70.8)	68 (71.6)	330 (71.0)

SRC: Signet ring cell carcinoma; ASC: Adenosquamous carcinoma; TNM: Tumor-node-metastasis; LN: Lymph node.

Table 3 Comparison of median survival of the patients before and after propensity score matching

	Patients, n	Median CSS 95%CI, mo	Median OS 95%CI, mo
Before PSM
SRC	5968	16.0 (15.2-16.8)	15.0 (14.3-15.7)
ASC	95	13.0 (9.7-16.3)	12.0 (9.5-14.5)
P value		0.101	0.084
After PSM
SRC	370	20.0 (15.7-24.3)	19.0 (14.9-23.1)
ASC	95	13.0 (9.7-16.3)	12.0 (9.5-14.5)
P value		0.027	0.017

CSS: Cancer-specific survival; OS: Overall survival; PSM: Propensity-score matching; SRC: Signet ring cell carcinoma; ASC: Adenosquamous carcinoma.

Table 4 Cox regression analysis of cancer-specific survival (n = 465)

Characteristic	Univariate Cox		Multivariate Cox
	HR (95%CI)	P value	HR (95%CI)	P value
Histological type
SRC	Reference		Reference
ASC	1.343 (1.029-1.752)	0.030	1.316 (1.004-1.726)	0.047
Age (yr)
≤ 60	Reference		NI
> 60	1.027 (0.819-1.288)	0.815
Gender
Male	Reference		NI
Female	0.952 (0.740-1.223)	0.698
Race
White	Reference		NI
Black	1.199 (0.870-1.652)	0.268
Others	0.883 (0.597-1.304)	0.531
Marital status
Not married	Reference		Reference
Married	0.768 (0.593-0.994)	0.045	0.709 (0.540-0.932)	0.014
Tumor size (mm)
≤ 50	Reference		Reference
> 50	1.994 (1.587-2.503)	<0.001	1.217 (0.947-1.564)	0.125
Stage
I	Reference		Reference
II	1.482 (0.993-2.212)	0.054	1.564 (1.021-2.394)	0.040
III	2.472 (1.714-3.564)	< 0.001	2.460 (1.601-3.780)	< 0.001
IV	5.179 (3.739-7.175)	< 0.001	2.884 (1.665-4.997)	< 0.001
Tumor depth
T1	Reference		Reference
T2	0.962(0.705-1.312)	0.805	1.296 (0.923-1.821)	0.135
T3	1.478(1.051-2.077)	0.025	1.482 (0.986-2.228)	0.058
T4	1.801 (1.243-2.609)	0.002	1.070 (0.699-1.638)	0.757
LN metastasis
N0	Reference		NI
N1	0.978(0.760-1.258)	0.863
N2	1.218 (0.901-1.647)	0.200
N3	1.642 (0.985-2.737)	0.057
Distant metastasis
No	Reference		Reference
Yes	4.303 (3.397-5.451)	< 0.001	1.278 (0.778-2.100)	0.333
Radiotherapy
No	Reference		Reference
Yes	0.484(0.383-0.612)	< 0.001	0.587 (0.444-0.776)	< 0.001
Surgery
No	Reference		Reference
Yes	0.244(0.192-0.311)	< 0.001	0.450 (0.319-0.635)	< 0.001

HR: Hazard ratio; NI: Not included; LN: Lymph node; SRC: Signet ring cell carcinoma; ASC: Adenosquamous carcinoma; TNM: Tumor-node-metastasis.