Tumor markers and multimodal magnetic resonance imaging in predicting rectal cancer stage and differentiation

Table 1 Magnetic resonance imaging staging criteria

MRI staging criteria	Description
T1 stage	The tumor is limited to the mucosal layer, presenting as a polypoid structure within the lumen or as a local mass
T2 stage	The thickness of the wall exceeds 0.5 cm, but the tumor has not yet extended to the surrounding fat tissue, with a clear distinction from surrounding fat
T3 stage	The tumor extends to the surrounding fat tissue but has not reached the fascia. This stage is defined as tumor penetration through the wall layer and invasion into surrounding fat
T4 stage	The tumor further invades the pelvic region and may be accompanied by distant metastasis

MRI: Magnetic resonance imaging.

Table 2 Demographic characteristics of patients with rectal cancer, n (%)

Clinicopathological parameters	Cases
Age
< 60	41 (37.61)
≥ 60	68 (62.39)
Gender
Male	61 (55.96)
Female	48 (44.04)
Lymphatic metastasis
Yes	40 (36.70)
No	69 (63.30)
Vascular invasion
Yes	7 (6.42)
No	102 (93.58)
Nerve infiltration
Yes	6 (5.50)
No	103 (94.50)
Degree of differentiation
Poorly	13 (11.93)
Moderately	92 (84.40)
Highly	4 (3.67)
T staging
T1	19 (17.43)
T2	46 (42.20)
T3	37 (33.94)
T4	7 (6.42)

Table 3 Consistency between magnetic resonance imaging and clinical pathological examinations in the diagnosis of T-stage of rectal cancer

MRI staging	Pathological staging (gold standard)		Total (n)
	T1-T2	T3-T4
T1-T2	60	6	66
T3-T4	5	38	43
Total (n)	65	44	109

P < 0.001. Consistency statistics: Cohen’s κ = 0.789 (95% confidence interval: 0.692-0.886). Agreement level: Substantial. MRI: Magnetic resonance imaging.

Table 4 Consistency between magnetic resonance imaging and clinicopathological examinations in the diagnosis of different degrees of rectal cancer

MRI grading	Pathological grading (gold standard)		Total
	High-grade	Low-grade
High-grade	3	2	5
Low-grade	1	103	104
Total	4	105	109

P < 0.001. Consistency statistics: Cohen’s κ = 0.651 (95% confidence interval: 0.012-1.290). Agreement strength: Substantial (Landis and Koch criteria). Definition of terms: High-grade: Well/moderately differentiated tumors; Low-grade: Poorly differentiated/undifferentiated tumors; MRI: Magnetic resonance imaging.

Table 5 Comparison of carbohydrate antigen 19-9, cancer antigen 72-4, carcinoembryonic antigen, and alpha-fetoprotein levels betweenT1-T2 and T3-T4 stages, mean ± SD

Indicator	T1-T2 (n = 65)	T3-T4 (n = 44)	P value
CA19-9 (kU/L)	10.37 ± 2.05	43.31 ± 4.52	< 0.001
CA72-4 (kU/L)	6.43 ± 1.71	12.62 ± 2.14	< 0.001
CEA (μg/L)	13.28 ± 3.75	23.26 ± 2.32	< 0.001
AFP (μg/L)	16.12 ± 3.83	21.16 ± 2.53	< 0.001

CA19-9: Carbohydrate antigen 19-9; CA72-4: Cancer antigen 72-4; CEA: Carcinoembryonic antigen; AFP: Alpha-fetoprotein.

Table 6 Comparison of carbohydrate antigen 19-9, cancer antigen 72-4, carcinoembryonic antigen, and alpha-fetoprotein levels in different degrees, mean ± SD

Indicator	Low differentiation (n = 105)	High differentiation (n = 4)	P value
CA19-9 (kU/L)	55.43 ± 5.12	9.62 ± 2.71	< 0.001
CA72-4 (kU/L)	14.15 ± 3.63	7.34 ± 1.25	< 0.001
CEA (μg/L)	14.82 ± 2.16	7.73 ± 1.48	< 0.001
AFP (μg/L)	3.94 ± 0.58	3.26 ± 0.51	0.022

CA19-9: Carbohydrate antigen 19-9; CA72-4: Cancer antigen 72-4; CEA: Carcinoembryonic antigen; AFP: Alpha-fetoprotein.

Table 7 Diagnostic value of tumor markers combined with magnetic resonance imaging in preoperative T stage of rectal cancer

Indicator	AUC	95%CI	P value	Sensitivity (%)	Specificity (%)
AFP	0.669	0.604-0.735	< 0.001	73.5	76.7
MRI	0.771	0.709-0.833	< 0.001	83.1	85.8
CA72-4	0.789	0.741-0.836	< 0.001	65.2	78.6
CA19-9	0.846	0.802-0.889	< 0.001	89.5	82.6
CEA	0.879	0.838-0.921	< 0.001	85.3	91.2
Combined detection	0.947	0.899-0.994	< 0.001	93.7	94.6

AUC: Area under the curve; CI: Confidence interval; AFP: Alpha-fetoprotein; MRI: Magnetic resonance imaging; CA72-4: Cancer antigen 72-4; CA19-9: Carbohydrate antigen 19-9; CEA: Carcinoembryonic antigen.

Table 8 Diagnostic value of tumor markers combined with magnetic resonance imaging in differentiation degree of rectal cancer patients

Indicator	AUC	95%CI	P value	Sensitivity (%)	Specificity (%)
AFP	0.815	0.721-0.896	< 0.001	75.4	76.2
CA19-9	0.887	0.817-0.955	< 0.001	89.2	91.2
CEA	0.894	0.842-0.964	< 0.001	90.5	88.1
CA72-4	0.916	0.866-0.975	< 0.001	89.6	89.4
MRI	0.923	0.873-0.975	< 0.001	91.3	93.1
Combined detection	0.978	0.946-0.998	< 0.001	93.6	97.1

AUC: Area under the curve; CI: Confidence interval; AFP: Alpha-fetoprotein; MRI: Magnetic resonance imaging; CA72-4: Cancer antigen 72-4; CA19-9: Carbohydrate antigen 19-9; CEA: Carcinoembryonic antigen.