Colorectal Cancer Screening in Average Risk Populations: Evidence Summary

Table 2

Summary of included studies by research question.

Research question and references	Systematic reviews	Outcomes	RCTs	Prospective studies	Retrospective studies	Case-control studies
Primary question: CRC screening tests
gFOBT versus no screening; [10–20]	1	CRC mortality	4
		Complications from tests	3
		All-cause mortality	4
		CRC incidence	5
FS versus no screening; [6, 10, 21–28]	1	CRC mortality	4
		Complications from tests	5
		All-cause mortality	4
		CRC incidence	4
Colonoscopy versus no screening; [29–51]	2	CRC mortality		2	1
		Complications from tests		11	4
		CRC incidence		2		3
mSEPT9 alone; [52]		Diagnostic test accuracy outcomes		1
Fecal M2-PK alone; [53, 54]		Diagnostic test accuracy outcomes		1		1
Stool DNA versus gFOBT or FIT; [55–58]		Diagnostic test accuracy outcomes		3		1
FIT versus gFOBT; [59–65]	1	Complications from tests	1
		CRC/advanced adenoma detection rate (ITS)	5
		CRC/advanced adenoma detection rate (PP)	5
		Participation rate	6
		Diagnostic test accuracy outcomes, false-positives/total screened	5
CT colonography versus colonoscopy; [66]		Complications from tests	1
		CRC/advanced adenoma detection rate (ITS)	1
		CRC/advanced adenoma detection rate (PP)	1
		Participation rate	1
Capsule colonoscopy versus colonoscopy; [67]		Complications from tests		1
		Adenoma detection rate (PP)		1
Fecal-based tests versus endoscopy; [10, 59, 63, 68–80]
FIT versus colonoscopy	3	Complications from tests	2
		CRC/advanced adenoma detection rate (ITS)	3
		Participation rate	3
FIT versus FS		Complications from tests	1
		CRC/advanced adenoma detection rate (ITS)	3
		Participation rate	3
gFOBT versus colonoscopy		Complications from tests	1
		Participation rate	2
gFOBT versus FS		Complications from tests	1
		CRC/advanced adenoma detection rate (ITS)	2
		Participation rate	4
gFOBT versus gFOBT + FS		Complications from tests	1
		CRC/advanced adenoma detection rate (ITS)	2
		Participation rate	3
Secondary question number 1: age of initiation and cessation by test
gFOBT versus no screening; [19, 20]		CRC mortality by age group	2
FS versus no screening; [6, 21, 23, 26]		CRC mortality by age group	2
		CRC incidence by age group	4
Colonoscopy versus no screening; [50]		CRC risk by age group				1
Secondary question number 2: screening interval by test
gFOBT; [15, 16, 20]		CRC mortality by interval (annual versus biennial)	1
		All-cause mortality by interval (annual versus biennial)	1
		CRC incidence by interval (annual versus biennial)	1
FIT; [81]		CRC/advanced adenoma detection rate by interval (1 versus 2 versus 3 years)	1
		Participation rate by interval (1 versus 2 versus 3 years)	1

CRC: colorectal cancer; CT: computed tomographic; DNA: deoxyribonucleic acid; FIT: fecal immunochemical test; FS: flexible sigmoidoscopy; gFOBT: guaiac fecal occult blood test; ITS: intention to screen; PP: per protocol; RCT: randomized controlled trial.
Some RCTs published multiple articles.
Tests that were included in our search strategy but yielded no results were not included.