Performance value of high risk factors in colorectal cancer screening in China

Table 1 Colonoscopy results of iFOBT and questionnaire n (%)

	Colorectal cancer	Advanced adenomas	Adenoma	Non-adenomatous polyps
iFOBT positive only	13 (61.9)	22 (45.8)	44 (29.9)	9 (16.7)
Both positive1	4 (19)	5 (10.4)	12 (8.2)	2 (3.6)
Only questionnaire positive	4 (19)	21 (43.8)	91 (61.9)	43 (79.7)
Total	21 (100)	48 (100)	147 (100)	54 (100)

¹Both iFOBT and questionnaire positive. iFOBT: Immunochemical fecal occult blood test.

Table 2 Colonoscopy results of high risk questionnaire items

	Cancer	Advanced adenomas	Adenomas	Non-adenomatous polyps	Normal results
iFOBT	17	27	56	11	128
History of malignant tumor	1	3	9	7	41
Colorectal cancer (CRC) in first degree relatives	2	7	29	11	81
History of adenomatous polyps (HAP)	0	9	25	6	48
History of mucous and bloody stool	5	4	15	10	101
History of chronic diarrhea	2	10	29	10	120
History of chronic constipation	0	8	24	13	102
History of chronic appendicitis or appendectomy	3	9	33	14	122
History of chronic cholecystitis or cholecystectomy	3	14	50	19	169
History of psychiatric trauma	4	5	18	2	73

Table 3 Characteristics of the study population n (%)

	Subjects with 2 analyzable tests (n = 13 214)
Sex
Male	5391 (40.8)
Female	7823 (59.2)
Age (yr)
40-49	2711 (20.5)
50-59	4704 (35.6)
60-69	3683 (27.9)
70-74	2116 (16.0)
Positive items
iFOBT	481 (3.6)
History of malignant tumor	172 (1.3)
CRC in first degree relatives	367 (2.8)
HAP	158 (1.2)
History of mucous and bloody stool	430 (3.3)
History of chronic diarrhea	709 (5.4)
History of chronic constipation	902 (6.8)
History of chronic appendicitis or appendectomy	1126 (8.5)
History of chronic cholecystitis or cholecystectomy	1538 (11.6)
History of psychiatric trauma	655 (5)

Table 4 Comparison of the performance of high risk factors in screening advanced neoplasias, adenomas, non-adenomatous polyps using HAP as reference

	Advanced neoplasias				Adenomas				Non-adenomatous polyps
	PPV (%)	NPV (%)	RSN	FP:TP	PPV (%)	NPV (%)	RSN	FP:TP	PPV (%)	NPV (%)	RSN	FP:TP
iFOBT	17.70	95.70	4.9 (2.42-9.87)	2.29 (1.36-3.83)	22.50	85.10	2.24 (1.4-3.52)	2.58 (1.37-4.87)	4.40	93	1.8 (0.71-4.58)	16 (3.39-75.58)
HMT	6.10	91.70	0.4 (0.17-1.19)		13.60	82.60	0.36 (0.18-0.7)		10.60	94	1.17 (0.39-3.48)
FDR	5.70	91.30	1 (0.4-2.519)		18.50	83.20	1.16 (0.69-1.96)	8.25 (0.44-154.47)	7	93.90	1.8 (0.67-4.88)	6.6 (1.16-37.6)
HAP	9.40	92	1		26	84	1		6.30	93.70	1
MBS	5.70	91.30	1 (0.42-2.39)		9.50	81.20	0.6 (0.33-1.08)		6.30	93.70	1.7 (0.66-4.38)	13.25 (2.02-86.77)
HCD	5.40	91	1.2 (0.54-2.63)	24 (1.87-307.35)	13.90	82	1.16 (0.72-1.88)	18 (1.1-293.1)	4.90	93.30	1.7 (0.71-4.08)	18 (3.2-101.33)
HCC	4.80	91	0.9 (0.35-2.33)		14.30	82.20	0.96 (0.56-1.65)		7.70	94.10	2.2 (0.88-5.49)	7.7 (2.26-26.21)
CAA	5.50	91	1.3 (0.59-2.83)	24.6 (1.63-370.18)	15.10	82.20	1.32 (0.8-2.16)	9.25 (1.52-55.7)	6.40	93.80	2.3 (0.88-5.99)	9.25 (2.96-28.79)
CCC	5.80	87.40	1.9 (0.87-4.12)	15.13 (4.47-51.23)	16.90	82.80	2 (1.26-3.16)	4.84 (2.43-9.65)	6.40	93.80	3.2 (1.38-7.42)	9.3 (4.5-19.22)
HPT	7.60	91.80	1 (0.42-2.39)		15.30	82.60	0.72 (0.43-1.2)		1.70	93	0.33 (0.07-1.63)

HMT: History of malignant tumor; FDR: History of CRC in first degree relatives; MBS: History of mucous and bloody stool; HCD: History of chronic diarrhea; HCC: History of chronic constipation; CAA: History of chronic appendicitis or appendectomy; CCC: History of chronic cholecystitis or cholecystectomy; HPT: History of psychiatric trauma; PPV: Positive predictive value; NPV: Negative predictive value; RSN: Relative sensitivity; FP:TP ratio: The ratio between the difference in the number of false positive subjects with one high risk factor vs HAP and the difference in the number of true positive subjects with one high risk factor vs HAP. Values for RSN and FP:TP are mean (95% CI). RSN > 1: Sensitivity of the high risk factor is greater than that of HAP.