What is the most cost-effective strategy to screen for second primary colorectal cancers in male cancer survivors in Korea?

Table 1 Summary of assumptions

	Parameter	Base case value (range)	Ref.
Sensitivity & specificity of colorectal screening tests	Sensitivity of FOBT for colorectal polyps/cancer	0.1/0.5	[27–30]
	Sensitivity of colonoscopy for colorectal polyps/cancer	0.9/0.95	[63132]
	Sensitivity of double contrast barium enema for colorectal polyps/cancer	0.5/0.8	[63334]
	Sensitivity of sigmoidoscopy for colorectal polyps/cancer	0.46/0.52	[313235]
	Specificity of FOBT	0.9	[28–30]
	Specificity of colonoscopy	1	[63132]
	Specificity of double contrast barium enema	0.9	[63334]
	Specificity of sigmoidoscopy	0.95	[63132]
Natural history of colorectal polyp/cancer sequence	Prevalence of polyps at age 50 yr	0.20 (0.1-0.4)	[1435]
	Annual polyp incidence rate in cancer survivors	Age specific	[143536]2
	Percent of cancers originating as polyps	90%	[3738]
	Relative risk of colorectal cancer in cancer survivor compared with the general population	4 (1-5)	[5]
	Age specific incidence rate of colorectal cancer without polypoid precursors in cancer survivors	Age specific	[53940]2
	Age specific incidence rate of colorectal cancer with polypoid precursors in cancer survivors	Age specific	[53940]2
	Dwelling time of colorectal cancer in early stages	2 yr	[2941]
	Percent of colorectal cancers detected in early stages with no screening	5% (2%-10%)	[23]
	Five-year all cause survival for early 2nd primary colorectal cancer	90% (80%-95%)	[182223]
	Five-year all cause survival for advanced 2nd primary colorectal cancer	60% (40%-70%)	[182223]
Natural history of cancer survivors	Five-year survival for index cancer	40% (20%-80%)	[18]
	Age specific mortality except the index cancer	Age specific	[21]
	Age of cancer survivors for starting colorectal cancer screening, year	50 (40-60)	[10–12]
	Compliance of 2nd colorectal cancer screening	80% (60%-100%)
Complications and unintended consequences	Rate of perforation of colon in colonoscopy	0.20% (0.1%-0.3%)	[131442]
	Rate of perforation of colon in polypectomy	0.40% (0.2%-0.5%)	[131442]
	Rate of perforation from sigmoidoscopy	0.01% (0.005%-0.05%)	[131442]
	Rate of perforation from double contrast barium enema	0.005% (0.001%-0.01%)	[42]
	Death rate due to perforated colon	0.2% (0.1%-5%)	[193942]
Cost (dollar1) & discount rate	Sigmoidoscopy	31.3	[25]
	Colonoscopy	61.7	[25]
	Double contrast barium enema	68.5	[25]
	FOBT	2.7	[25]
	Polypectomy, biopsy and pathologic exam	189	[25]
	Treatment of early cancer for first year	7330 (5860-8800)	[725]
	Treatment of advanced cancer for first year	14 660 (10 050-15 080)	[725]
	Treatment of cancer after first year	2094 (1670-2510)	[725]
	Cost to repair the endoscopic perforation	3141 (2510-3770)	[7]
	Discount rate	0.03 (0-0.05)

¹Exchange rate: 955 Korean Won for one US dollar in 2006;

²Estimated by calibration to national data on colorectal polyp and cancer incidence.