Serum pepsinogen combined with computed tomography imaging for diagnosing recurrence of gastric cancer after total gastrectomy

Table 1 Baseline characteristics of the study population, n (%)

Variables	Total (n = 110)	Recurrence (n = 65)	No recurrence (n = 45)	P value
Age (years), mean ± SD	66.13 ± 8.83	67.11 ± 8.64	64.71 ± 9.01	0.1626
Age range (years)	34-88	34-88	37-81	-
Sex				0.3295
Male	84 (76.36)	47 (72.31)	37 (82.22)
Female	26 (23.64)	18 (27.69)	8 (17.78)
Tumor location				0.2434
Cardia	70 (63.64)	46 (70.77)	24 (53.33)
Gastric body	30 (27.27)	15 (23.08)	15 (33.33)
Gastric antrum	8 (7.27)	4 (6.15)	4 (8.89)
Gastric angle	1 (0.91)	0 (0.00)	1 (2.22)
Pylorus	1 (0.91)	0 (0.00)	1 (2.22)
Pathological stage				0.0004b
I	18 (16.36)	6 (9.23)	12 (26.67)
II	19 (17.27)	8 (12.31)	11 (24.44)
III	58 (52.73)	38 (58.46)	20 (44.44)
IV	15 (13.64)	13 (20.00)	2 (4.44)
Histological subtype				0.1825
Differentiated	48 (43.64)	32 (49.23)	16 (35.56)
Undifferentiated	56 (50.91)	28 (43.08)	28 (62.22)
Mucinous adenocarcinoma	4 (3.64)	3 (4.62)	1 (2.22)
Signet ring cell carcinoma	2 (1.82)	2 (3.08)	0 (0.00)

^bP < 0.01.

Percentages may not total 100% due to rounding. All patients underwent R0 radical total gastrectomy and received neoadjuvant therapy. Continuous variables were compared using independent-samples t test; categorical variables were compared using χ² test or Fisher’s exact test as appropriate.

Table 2 Comparison of positive rates for serum pepsinogen and computed tomography imaging in diagnosing postoperative recurrence, n (%)

Group	n	Serum PG+	CT imaging+	McNemar χ2	df	P value
Total	110	62 (56.36)	44 (40.00)	9.03	1	0.0027b
Recurrence	65	60 (92.31)	41 (63.08)	11.17	1	0.0008b

^bP < 0.01.

Serum pepsinogen (PG)+ was defined as PG I > 26.93 ng/mL and/or PG II > 0.96 ng/mL. Computed tomography (CT) imaging+ indicates definitive signs of recurrence or metastasis. The McNemar test with continuity correction was used to compare paired positivity rates between serum PG and CT imaging. CT: Computed tomography; PG: Pepsinogen.

Table 3 Diagnostic performance of serum pepsinogen, computed tomography imaging, and the combined model for recurrence after total gastrectomy

Variables	AUC	95%CI	Sensitivity	Specificity	P value
Serum PG	0.94	0.88-0.98	0.92	0.96	< 0.0001b
CT imaging	0.78	0.69-0.86	0.63	0.93	< 0.0001b
Combined model	0.98	0.93-1.00	1.00	0.91	< 0.0001b

^bP < 0.01.

P values indicate whether each area under the curve is significantly different from 0.5. AUC: Area under the curve; CI: Confidence interval; CT: Computed tomography; PG: Pepsinogen.

Table 4 Multivariate logistic regression analysis of factors associated with postoperative recurrence

Variables	B	OR (95%CI)	P value
Serum PG	6.22	501.25 (45.08-5573.97)	< 0.0001b
CT imaging	4.06	58.22 (5.14-660.11)	0.001b

^bP < 0.01.

The regression equation was: ln(P/(1-P)) = -3.75 + 6.22 × (serum pepsinogen) + 4.06 × (computed tomography imaging), where both independent variables are binary (positive = 1, negative = 0) and P is the predicted probability of recurrence. OR: Odds ratio; CI: Confidence interval; CT: Computed tomography; PG: Pepsinogen.

Table 5 Tissue pepsinogen expression, serum pepsinogen levels, and computed tomography imaging findings in patients with recurrence stratified by histological type, n (%)

Histological Type	n	PG expression+	Serum PG+	CT imaging+
DGC	7	1 (14.29)	1 (14.29)	5 (71.43)
UGC	22	19 (86.36)	18 (81.82)	13 (59.09)
MADC	2	0 (0.00)	0 (0.00)	0 (0.00)
SRCC	3	3 (100.00)	3 (100.00)	2 (66.67)

Pepsinogen (PG) expression⁺ indicates positive immunohistochemical staining for PG I and/or PG II. Serum PG⁺ was defined as PG I > 26.93 ng/mL and/or PG II > 0.96 ng/mL. Computed tomography imaging+ indicates definitive signs of recurrence or metastasis. DGC: Differentiated gastric cancer; UGC: Undifferentiated gastric cancer; MADC: Mucinous adenocarcinoma; SRCC: Signet ring cell carcinoma; CT: Computed tomography; PG: Pepsinogen.