Can visceral fat parameters based on computed tomography be used to predict occult peritoneal metastasis in gastric cancer?

Table 1 Comparison of clinical and computed tomography characteristics between two groups, n (%)

Variable		PM (-) (n = 85)	PM (+) (n = 43)	P value
Sex	Male	60 (70.6)	24 (55.8)	0.096
	Female	25 (29.4)	19 (44.2)
Age (yr) (mean ± SD)		56.44±12.63	61.25±11.11	0.0291
Pathological type	Adenocarcinoma	83 (97.6)	38 (88.4)	0.077
	Non-adenocarcinoma	2 (2.4)	5 (11.6)
Differentiation	Poorly differentiated	50 (58.8)	30 (69.8)	0.227
	Moderately and well differentiated	35 (41.2)	13 (30.2)
CEA	Normal	74 (87.1)	37 (86.0)	0.873
	Elevated	11 (12.9)	6 (14.0)
CA199	Normal	74 (87.1)	32 (74.4)	0.073
	Elevated	11 (12.9)	11 (25.6)
CA125	Normal	83 (97.6)	37 (86.0)	0.0301
	Elevated	2 (2.4)	6 (14.0)
Location	Cardia	44 (51.8)	7 (16.3)	0.0011
	Body	12 (14.1)	14 (32.6)
	Antrum	20 (23.5)	13 (30.2)
	≥ 2 parts	9 (10.6)	9 (20.9)
Mild ascites	(-)	75 (88.2)	24 (55.8)	0.0011
	(+)	10 (11.8)	29 (44.2)
cN stage	N0	26 (30.6)	11 (25.6)	0.150
	N1-2	41 (48.2)	16 (37.2)
	N3-4	18 (21.2)	16 (37.2)
cT stage	≤ T3	57 (67.1)	14 (32.6)	0.0011
	≥ T4	28 (32.9)	29 (67.4)
Thickness (mm), median (IQR)		15.11 (13.02, 18.85)	13.43 (11.28, 17.83)	0.0231

¹P < 0.05.

PM: Peritoneal metastasis; CEA: Carcinoembryonic antigen; CA199: Carbohydrate antigen 199; CA125: Carbohydrate antigen 199; IQR: Interquartile range.

Table 2 Comparison of visceral fat characteristics between the two lesions

Variable	PM (+) (n = 43)	PM (-) (n = 85)	P value	ICC
VFROI 1
Volume (cc)	84.45 (36.70, 161.04)	87.92 (49.89, 160.75)	0.412	0.913
Mean attenuation (HU)	-82.07 ± 6.06	-85.33 ± 5.89	0.0441	0.810
SD attenuation (HU)	18.82 (17.78, 21.25)	19.51 (18.63, 21.11)	0.133	0.926
SFROI 1
Volume (cc)	108.79 (55.10, 170.90)	115.96 (62.70, 178.72)	0.760	0.979
Mean attenuation (HU)	-85.33 ± 5.89	-86.05 ± 8.23	0.934	0.955
SD attenuation (HU)	17.94 (16.60, 19.37)	18.58 (17.27, 20.16)	0.180	0.981
VFROI 2
Volume (cc)	132.63 (58.85, 273.65)	145.48 (82.58, 277.42)	0.302	0.932
Mean attenuation (HU)	-82.19 ± 5.35	-85.70 ± 5.65	0.0011	0.974
SD attenuation (HU)	19.86 (17.58, 20.46)	19.13 (18.47, 20.66)	0.317	0.950
SFROI 2
Volume (cc)	163.24 (82.57, 261.17)	175.86 (97.86, 267.52)	0.76	0.991
Mean attenuation (HU)	-86.28 ± 8.61	-86.41 ± 8.08	0.938	0.980
SD attenuation (HU)	17.80 (16.42, 19.33)	18.45 (17.29, 19.91)	0.124	0.993
Volume ratio
VF/SFROI 1	0.92 (0.44, 1.50)	1.00 (0.61, 1.65)	0.317	0.804
VF/SFROI 2	0.98 (0.47, 1.41)	1.00 (0.63, 1.68)	0.279	0.884

¹P < 0.05.

PM: Peritoneal metastasis; ICC: Intraclass correlation coefficient; VF: Visceral fat; SF: Subcutaneous fat; SD: Standard deviation; ROI: Region of interest; HU: Hounsfield units; ROIs 1 and 2: Regions of interest starting at the largest axial level of the tumor and extending down 15 mm and 25 mm, respectively.

Table 3 Comparison of attenuations of visceral fat between different clinical characteristic classifications

Variable		Mean attenuation of VF ROI 2	P value
Sex	Male	-84.90 ± 6.19	0.306
	Female	-83.83 ± 4.88
Age (yr)	≤ 61	-84.48 ± 5.11	0.937
	> 61	-84.46 ± 5.14
Pathological type	Adenocarcinoma	-84.64 ± 5.81	0.339
	Non-adenocarcinoma	-82.49 ± 4.99
Differentiation	Poorly differentiated	-84.18 ± 5.91	0.377
	Moderately and well differentiated	-85.11 ± 5.56
CEA	Normal	-84.64 ± 5.92	0.583
	Elevated	-83.81 ± 4.86
CA199	Normal	-85.04 ± 6.04	0.0021
	Elevated	-82.07 ± 3.40
CA125	Normal	-84.80 ± 5.81	0.0391
	Elevated	-80.46 ± 3.41
Location	Cardia/Body/Antrum	-84.93 ± 5.86	0.0491
	≥ 2 parts	-82.05 ± 4.67
Mild ascites	(-)	-85.41 ± 5.79	0.0011
	(+)	-81.52 ± 4.69
cN stage	N0	-85.48 (-89.85, -82.95)	0.0301
	N1-2	-83.08 (-86.68, -79.43)
	N3-4	-84.54 (-87.51, -80.60)
cT stage	≤ T3	-85.88 ± 5.83	0.0031
	≥ T4	-82.84 ± 5.29
Thickness (mm)	≤ 14.5	-84.82 ± 6.36	0.517
	> 14.5	-84.15 ± 4.98

¹P < 0.05.

CEA: Carcinoembryonic antigen; CA199: Carbohydrate antigen 199; CA125: Carbohydrate antigen 199; VF: Visceral fat; ROI 2: Regions of interest starting at the largest axial level of the tumor and extending down 25 mm.

Table 4 Stratified analysis of volume

	PM (-)	PM (+)	P value	AUC (95%CI)
Volume > median
No	45	19
Mean attenuation (HU)	-89.08 ± 5.31	-85.44 ± 3.93	0.0091	0.726 (0.59-0.854)
Volume ≤ median
No	40	24
Mean attenuation (HU)	-81.92 ± 3.01	-79.61 ± 4.94	0.0461	0.639 (0.490-0.787)

¹P < 0.05.

PM: Peritoneal metastasis; No: Number; AUC: Area under the curve; HU: Hounsfield units.

Table 5 Variables and coefficients of multiple regression logistic analysis

Variable	OR	95%CI	P value
Based on all characteristics
Mild ascites (+ vs -)	3.552	(1.375-9.175)	0.0091
Mean attenuations of VFROI 2	3.437	(0.914-12.914)	0.068
cT stage (≥ T4 vs ≤ T3)	2.631	(1.126-6.144)	0.0251
Intercept	0.009		0.0011
Based on clinical characteristics
Mild ascites (+ vs -)	4.188	(1.636-10.722)	0.0031
cT stage (≥ T4 vs ≤ T3)	2.992	(1.301-6.881)	0.0101
Intercept	0.068		0.0011

¹P < 0.05.

VF: Visceral fat; ROI: Region of interest; OR: Odds ratio; CI: Confidence interval.