Prognostic value of signet-ring cell carcinoma proportion in undifferentiated gastric cancer: Implications for endoscopic treatment decisions

Table 1 Clinicopathologic factors according to the signet ring cell carcinoma group, mean ± SD/n (%)

Total (n = 1066)		Group 1 (SRCC < 10%) (n = 84)	Group 2 (10% ≤ SRCC < 50%) (n = 336)	Group 3 (50% ≤ SRCC < 90%) (n = 336)	Group 4 (SRCC ≥ 90%) (n = 310)	1P value
Age	56.2 ± 11.98	54.82 ± 12.35	57.04 ± 12.39	57.29 ± 11.71	54.46 ± 11.52	0.0064
Largest size (cm)	4.15 ± 3.85	7.22 ± 4.63	5.08 ± 4.16	3.92 ± 3.61	2.56 ± 2.51	< 0.001
Sex
F	600 (56.29)	39 (46.43)	197 (58.63)	184 (54.76)	180 (58.06)	0.1883
M	466 (43.71)	45 (53.57)	139 (41.37)	152 (45.24)	130 (41.94)
pT
T1a	435 (40.81)	4 (4.76)	52 (15.48)	144 (42.86)	235 (75.81)	< 0.001
T1b	214 (20.08)	10 (11.9)	79 (23.51)	93 (27.68)	32 (10.32)
T2	86 (8.07)	7 (8.33)	44 (13.1)	19 (5.65)	16 (5.16)
T3	97 (9.1)	12 (14.29)	50 (14.88)	27 (8.04)	8 (2.58)
T4a	205 (19.23)	47 (55.95)	94 (27.98)	46 (13.69)	18 (5.81)
T4b	29 (2.72)	4 (4.76)	17 (5.06)	7 (2.08)	1 (0.32)
AGC or EGC
AGC	417 (39.12)	70 (83.33)	205 (61.01)	99 (29.46)	43 (13.87)	< 0.001
EGC	649 (60.88)	14 (16.67)	131 (38.99)	237 (70.54)	267 (86.13)
pN (AJCC)
N0	764 (71.67)	27 (32.14)	193 (57.44)	264 (78.57)	280 (90.32)	< 0.001
N1	62 (5.82)	6 (7.14)	33 (9.82)	12 (3.57)	11 (3.55)
N2	74 (6.94)	17 (20.24)	31 (9.23)	18 (5.36)	8 (2.58)
N3a	65 (6.1)	14 (16.67)	30 (8.93)	16 (4.76)	5 (1.61)
N3b	101 (9.47)	20 (23.81)	49 (14.58)	26 (7.74)	6 (1.94)
pN (2nd Japanese classification)
N0	756 (72.34)	27 (33.33)	189 (57.98)	263 (78.98)	277 (90.82)	< 0.001
N1	143 (13.68)	31 (38.27)	65 (19.94)	30 (9.01)	17 (5.57)
N2	132 (12.63)	20 (24.69)	67 (20.55)	36 (10.81)	9 (2.95)
N3	14 (1.34)	3 (3.7)	5 (1.53)	4 (1.2)	2 (0.66)
pM
M0	1039 (97.47)	78 (92.86)	323 (96.13)	331 (98.51)	307 (99.03)	0.0026
M1	27 (2.53)	6 (7.14)	13 (3.87)	5 (1.49)	3 (0.97)
Lymphatic invasion	258 (24.2)	46 (54.76)	112 (33.33)	71 (21.13)	29 (9.35)	< 0.001
Venous invasion	108 (10.13)	20 (23.81)	46 (13.69)	33 (9.82)	9 (2.9)	< 0.001
Neural invasion	392 (36.77)	67 (79.76)	189 (56.25)	99 (29.46)	37 (11.94)	< 0.001
HER2
-/3	579 (54.32)	52 (61.9)	193 (57.44)	176 (52.38)	158 (50.97)	0.3751
1 +/3	364 (34.15)	24 (28.57)	109 (32.44)	117 (34.82)	114 (36.77)
2 +/3	111 (10.41)	6 (7.14)	32 (9.52)	37 (11.01)	36 (11.61)
3 +/3	12 (1.13)	2 (2.38)	2 (0.6)	6 (1.79)	2 (0.65)
EBV
Negative	1059 (99.34)	83 (98.81)	333 (99.11)	336 (100)	307 (99.03)	0.3428
Positive	7 (0.66)	1 (1.19)	3 (0.89)	0 (0)	3 (0.97)
Recurrence	23 (2.16)	2 (2.38)	14 (4.17)	7 (2.08)	0 (0)	0.0041
Death	55 (5.16)	9 (10.71)	22 (6.55)	20 (5.95)	4 (1.29)	< 0.001
PD-L1 (n = 63)
Negative (CPS < 1)	27 (42.86)	6 (46.15)	15 (41.67)	5 (41.67)	1 (50)	0.9884
Positive (CPS ≥ 1)	36 (57.14)	7 (53.85)	21 (58.33)	7 (58.33)	1 (50)
MSI
MSI-H	9 (0.84)	1 (1.19)	5 (1.49)	2 (0.6)	1 (0.32)	0.3854
MSS/MSI-L	1057 (99.16)	83 (98.81)	331 (98.51)	334 (99.4)	309 (99.68)

¹P values were calculated using one-way ANOVA test, χ² test and Fisher’s test. SRCC: Signet ring cell carcinoma; F: Female; M: Male; AGC: Advanced gastric cancer; EGC: Early-stage gastric cancer; pT: Pathological tumor category; pN: Pathological node category; pM: Pathological metastasis category; AJCC: American Joint Committee on Cancer; HER2: Human epidermal growth factor receptor 2; EBV: Epstein-Barr virus; PD-L1: Programmed death-ligand 1; CPS: Composite positive score; MSI: Microsatellite instability; MSI-H: Microsatellite instability-high; MSI-L: Microsatellite instability-low; MSS: Microsatellite stability.

Table 2 Signet ring cell carcinoma rates according to the early-stage gastric cancer subgroup

EGC subgroup	Number	SRCC rates (%) (mean)	SD
A1: Ulcer (-), size ≤ 2 cm	317	74.0379	29.5714
A2: Ulcer (-), 2 cm < size ≤ 4 cm	157	72.8344	26.568
A3: Ulcer (-), size > 4 cm	43	69.3023	28.3175
B1: Ulcer (+), size ≤ 2 cm	56	67.3214	29.7102
B2: Ulcer (+), 2 cm < size ≤ 4 cm	56	60.3571	31.0989
B3: Ulcer (+), size > 4 cm	21	60	32.4808

SRCC: Signet ring cell carcinoma; EGC: Early-stage gastric cancer.

Table 3 Risk assessment of pathological variables for lymph node metastasis in undifferentiated-type early-stage gastric cancer

Variable	Total	Lymph node metastasis	Proportion with 95%CI
Size ≤ 2 cm	372	11	0.03 (0.01-0.05)
2 cm < size ≤ 4 cm	213	13	0.06 (0.03-0.09)
Size > 4 cm	64	12	0.19 (0.09-0.28)
Ulcer (-)	516	18	0.03 (0.02-0.05)
Ulcer (+)	133	18	0.14 (0.08-0.19)
SRCC ≥ 50%	504	21	0.04 (0.02-0.06)
SRCC < 50%	145	15	0.10 (0.05-0.15)

CI: Confidential interval; SRCC: Signet ring cell carcinoma.

Table 4 Odds ratios of pathological variables for lymph node metastasis in undifferentiated-type early-stage gastric cancer

	OR	P value	95%LCI for OR	95%UCI for OR
Size > 2 cm	2.6436	0.0107	1.2532	5.5764
Ulcer present	3.2474	0.0012	1.5922	6.623
SRCC rate < 50%	2.0816	0.0461	1.0127	4.2787

OR: Odds ratio; LCI: Lower confidential interval; UCI: Upper confidential interval; SRCC: Signet ring cell carcinoma.