Significance of carcinoembryonic antigen detection in the early diagnosis of colorectal cancer: A systematic review and meta-analysis

Table 1 Characteristics of included studies

Ref.	Year of publication	Study design	Sample size	Age (yr)	Location of cancer	Stage of the tumour	Treatment therapy
Augestad et al[15]	2014	Randomized controlled trial	110	65.4 ± 8.1; males = 59.1%, females = 40.9%	Colon (110 patients)	I (24), II (55), III (32)	Surgical treatment for all patients
Bhatti et al[16]	2015	Prospective cohort study	569	70; males = 51%, females = 49%	Colon (336 patients) and rectum (233 patients)	0 (31), I (33), II (78), III (288), IV (137)	Surgical treatment (569 patients), neoadjuvant chemotherapy (106 patients) and adjuvant chemotherapy (204 patients)
Chang et al[17]	2017	Prospective cohort study	357	63.8 ± 11.5; males = 57.7%, females = 42.3%	Colon (259 patients) and rectum (98 patients)	I (97), II (125), III (135)	Surgical treatment (357 patients), neoadjuvant radiotherapy and chemotherapy (81 patients)
Gilardoni et al[18]	2015	Retrospective cohort study	196	70; males = 59.7%, females = 40.3%	Colon (196 patients)	I (65), III (131)	Surgical treatment (196 patients)
Guo et al[19]	2018	Retrospective cohort study	178	59.7 ±10.6; males = 66.3%; females = 32.7%	Colon (79 patients) and rectum (42 patients)	0 (2), I (11), II (60), III (105)	Surgical treatment (178 patients) and chemotherapy (66 patients)
Hara et al[20]	2011	Prospective cohort study	127	63.4 ±9.4; males = 55.1%, females = 44.9%	Colon (85 patients) and rectum (42 patients)	III (127)	Surgical treatment (127 patients), adjuvant chemotherapy (110 patients), adjuvant radiotherapy (1 patient)
Jones et al[21]	2015	Retrospective cohort study	118	N/A; males = 61.9%, females = 38.1%	Colon (66 patients) and rectum (52 patients)	I (26), II (47), III (45)	Surgical treatment (118 patients), adjuvant chemotherapy (73 patients)
Kim and Lee[22]	2013	Retrospective cohort study	336	60.4 ± 11.1; males = 60.7%, females = 39.3%	Colon (224 patients) and rectum (112 patients)	II (189 patients) and III (147 patients)	Surgical treatment for all patients
Moloney et al[23]	2019	Retrospective cohort study	138	67; males = 54.3%, females = 45.7%	Colon (90 patients) and rectum (48 patients)	I (58 patients), II (69 patients), III (11 patients)	Surgical treatment for all patients
Nicolini et al[24]	2010	Prospective cohort study	108	60	Colon (69 patients) and rectum (39 patients)	I (29 patients), II (41 patients), and III (38 patients)	Surgical treatment for all patients
Rodrigues et al[25]	2017	Prospective cohort study	404	64.6; males = 59.7%, females = 40.3%	Colon (199 patients) and rectum (205 patients)	II (177 patients) and III (227 patients)	Surgical treatment (404 patients), neoadjuvant chemotherapy in the rectum (175), adjuvant chemotherapy (196 patients) and adjuvant chemotherapy in the colon (86 patients)
Shinkins et al[26]	2017	Randomized controlled trial	582	65; males = 61.3%, females = 38.7%	N/A	I (110 patients), II (282 patients), III (166 patients) and U (24 patients)	Surgical treatment for all patients

Table 2 Diagnostic values of follow up duration and reference standards

Ref.	Year of publication	Sample size	Percent recurrence (%)	Duration of follow-up (mo)	Index test	Frequency (mo)	Standard of reference	True positive	False positive	False negative	True negative
Augestad et al[15]	2014	110	12.7	17	CEA reference threshold of 5 g/L	6	Colonoscopy, contrast-enhanced ultrasound, computed tomography scans, PET scans	3	6	4	97
Bhatti et al[16]	2015	569	26.2	6-50	CEA reference threshold of 5 g/L	6	CT and PET scans with or without biopsies	123	23	26	397
Chang et al[17]	2017	357	18.8	3-64	CEA reference threshold of 5 g/L	6	CT scan	44	59	23	231
Hara et al[20]	2011	127	36.2	N/A	CEA reference threshold of 5 g/L	6	Radiological examination	31	31	15	50
Guo et al[19]	2018	178	51.7	N/A	CEA reference threshold of 5 g/L	6	Radiological examination involving X-rays, CT scans	66	36	26	50
Kim and Lee[22]	2013	336	23.5	36-134	CEA reference threshold of 5 g/L	6	Biopsies and radiological examination	34	23	45	234
Moloney et al[23]	2019	138	4.3	25	N/A	6	CT scans, colonoscopy and ultrasound	2	5	4	127
Rodrigues et al[25]	2017	404	12.9	3-79	CEA reference threshold of 5 ug/L for smokers and a 3 g/L for non-smokers	6	Radiological examinations	23	36	29	316
Shinkins et al[26]	2017	582	17.9	N/A	CEA reference threshold of 5 g/L	6	CT scans, colonoscopy	51	12	53	466

CEA: Carcinoembryonic antigen; CT: Computed tomography; PET: Positron-emission tomography; N/A: Not applicable.