Retrospective analysis of preoperative tumor marker levels in rectal cancer patients: Implications for diagnosis

Table 1 Demographic and clinicopathological characteristics of the study population characteristic

Characteristic	n (%)
Age, years
< 60	98 (39.2)
≥ 60	152 (60.8)
Sex
Male	146 (58.4)
Female	104 (41.6)
Tumor location
Upper rectum	62 (24.8)
Middle rectum	103 (41.2)
Lower rectum	85 (34.0)
Clinical stage
I	45 (18.0)
II	78 (31.2)
III	92 (36.8)
IV	35 (14.0)
Histological type
Adenocarcinoma	228 (91.2)
Mucinous	18 (7.2)
Signet ring cell	4 (1.6)
Differentiation
Well	32 (12.8)
Moderate	165 (66.0)
Poor	53 (21.2)

Table 2 Preoperative serum levels of tumor markers tumor marker

Tumor marker	Median (IQR)	Elevated, n (%)
AFP (ng/mL)	3.2 (1.8-5.7)	18 (7.2)
CEA (ng/mL)	4.8 (2.3-12.6)	122 (48.8)
CA125 (U/mL)	16.5 (9.8-28.3)	45 (18.0)
CA19-9 (U/mL)	18.7 (8.9-42.1)	62 (24.8)
CA15-3 (U/mL)	15.3 (10.1-23.8)	28 (11.2)
CA72-4 (U/mL)	3.8 (1.9-8.2)	52 (20.8)

IQR: Interquartile range; AFP: Alpha-fetoprotein; CEA: Carcinoembryonic antigen; CA: Cancer antigen.

Table 3 Diagnostic performance of tumor markers, %

Marker/combination	AUC (95%CI)	Sensitivity	Specificity	PPV	NPV
CEA	0.78 (0.73-0.83)	68.4	82.1	79.5	71.8
CA19-9	0.71 (0.65-0.77)	52.8	85.3	78.2	64.1
CA72-4	0.69 (0.63-0.75)	48.0	87.6	79.3	62.4
CA125	0.65 (0.59-0.71)	42.4	86.9	76.2	60.1
CA15-3	0.61 (0.55-0.67)	36.8	88.5	76.1	58.3
AFP	0.57 (0.51-0.63)	22.4	92.8	75.6	54.9
CEA + CA19-9	0.84 (0.79-0.89)	76.8	79.3	78.7	77.5
CEA + CA72-4	0.82 (0.77-0.87)	74.4	80.6	79.3	75.9
CEA + CA19-9 + CA72-4	0.87 (0.83-0.91)	81.2	77.8	78.5	80.6

AUC: Area under the curve; CI: Confidence interval; PPV: Positive predictive value; NPV: Negative predictive value; CEA: Carcinoembryonic antigen; CA: Cancer antigen; AFP: Alpha-fetoprotein.

Table 4 Correlation between tumor marker levels and clinicopathological features

Feature	CEA	CA19-9	CA72-4	CA125	CA15-3	AFP
Tumor stage	P < 0.001	P = 0.032	P = 0.028	P = 0.145	P = 0.213	P = 0.678
Lymph node involvement	P = 0.002	P = 0.056	P = 0.009	P = 0.087	P = 0.312	P = 0.543
Distant metastasis	P < 0.001	P = 0.007	P = 0.019	P = 0.098	P = 0.176	P = 0.821
Tumor differentiation	P = 0.067	P = 0.018	P = 0.104	P = 0.231	P = 0.289	P = 0.765
Tumor size	P = 0.023	P = 0.041	P = 0.013	P = 0.156	P = 0.267	P = 0.612

CEA: Carcinoembryonic antigen; CA: Cancer antigen; AFP: Alpha-fetoprotein.

Table 5 Diagnostic performance of tumor marker panel with and without fecal occult blood test panel, %

Panel	AUC (95%CI)	Sensitivity	Specificity	PPV	NPV
CEA + CA19-9 + CA72-4	0.87 (0.81-0.93)	81.2	77.8	78.5	80.6
CEA + CA19-9 + CA72-4 + FOBT	0.91 (0.86-0.96)	86.5	82.3	83.1	85.8

AUC: Area under the curve; CI: Confidence interval; PPV: Positive predictive value; NPV: Negative predictive value; CEA: Carcinoembryonic antigen; CA: Cancer antigen; FOBT: Fecal occult blood test.