Endoscopic ultrasonography lesion thickness predicts deep invasion in gastric cancer: Development and temporal validation of a preoperative model

Table 1 Multivariable logistic regression model for preoperative prediction of pathological ≥ pT3 gastric cancer

Variable1	OR	95%CI	P value
EUS thickness (overall effect)2	N/A	N/A	< 0.001
Lauren: Diffuse-type vs intestinal-type	1.700	0.932-3.101	0.084
Lauren: Mixed-type vs intestinal-type	2.315	1.257-4.261	0.007
Age (per 1-year increase)	1.002	0.982-1.024	0.824
Gender: Male vs female	0.770	0.474-1.250	0.290
Tumour site: Middle vs upper	1.066	0.554-2.051	0.848
Tumour site: Lower vs upper	1.127	0.567-2.240	0.733
CEA (per unit increase)	1.126	1.026-1.235	0.013
CA19-9 (per unit increase)	1.009	0.997-1.022	0.135

¹Values are adjusted odds ratios with 95% confidence intervals from the final multivariable logistic regression model. The outcome was pathological ≥ pT3 (T3/T4) vs T1-2. Lauren intestinal-type, female sex and upper-third tumour location were used as reference categories. Age was modelled per 1-year increase. Serum carcinoembryonic antigen and carbohydrate antigen 19-9 were entered as continuous variables (per 1 ng/mL and per 1 U/mL increase, respectively).

²Endoscopic ultrasonography thickness was included as a continuous predictor using restricted cubic splines with four knots; the overall association was assessed by a Wald test (P < 0.001), and the detailed functional form of the relationship between thickness and predicted risk is shown in Figure 2.

EUS: Endoscopic ultrasonography; OR: Odds ratio; CI: Confidence interval; CEA: Carcinoembryonic antigen; CA19-9: Carbohydrate antigen 19-9; N/A: Not applicable.

Table 2 Baseline characteristics of the development cohort (2017-2020) and temporal validation cohort (2021-2025), n (%)/median (interquartile range)

Variable1	Development cohort (2017-2020), n = 518	Temporal validation cohort (2021-2025), n = 246	Overall, n = 764	SMD
Age, years	57.50 (49.00-65.00)	60.00 (53.00-67.00)	59.00 (50.00-66.00)	0.219
Sex				0.163
Male	285 (55.0)	155 (63.0)	440 (57.6)
Female	233 (45.0)	91 (37.0)	324 (42.4)
Tumour location				0.164
Upper stomach (cardia/fundus)	95 (18.3)	37 (15.0)	132 (17.3)
Middle stomach (body/angle)	242 (46.7)	108 (43.9)	350 (45.8)
Lower stomach (antrum/pylorus/remnant)	181 (34.9)	101 (41.1)	282 (36.9)
Lauren classification				0.191
Intestinal	168 (32.4)	97 (39.4)	265 (34.7)
Diffuse	198 (38.2)	80 (32.5)	278 (36.4)
Mixed	152 (29.3)	69 (28.0)	221 (28.9)
EUS lesion thickness, mm	10.10 (7.40-13.60)	8.00 (4.31-12.98)	9.70 (6.17-13.50)	0.346
CEA	2.13 (1.37-4.00)	1.96 (1.19-3.25)	2.07 (1.28-3.63)	0.062
CA19-9	10.79 (6.15-19.63)	9.79 (5.45-17.62)	10.48 (5.98-18.94)	0.070
Pathological stage				0.439
pT1-2	164 (31.7)	130 (52.8)	294 (38.5)
≥ pT3	354 (68.3)	116 (47.2)	470 (61.5)

¹Between-cohort differences are described using standardized mean differences; no hypothesis testing was performed for Table 1. For continuous variables, standardized mean differences were calculated using pooled standard deviations.

SMD: Standardized mean difference; EUS: Endoscopic ultrasonography; CEA: Carcinoembryonic antigen; CA19-9: Carbohydrate antigen 19-9.