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.

Table 2 Cost-effectiveness of colorectal screening strategies among male cancer survivors and the general population in Korea (80% compliance)

Male general population				Male cancer survivors
Strategy (abreviation)	Lifetime cost per person (dollar)1	Life expectancy (yr)	Incremental C/E2, dollar1 per life-year gained	Strategy (abreviation)	Lifetime cost per person (dollar)1	Life expectancy (yr)	Incremental C/E2, dollar1 per life-year gained
COL every 10 yr	437.3	17.260	…	COL every 5 yr	463.5	7.572
No screening	448.0	17.243	…	COL every 10 yr	480.1	7.568	…
COL every 5 yr	478.3	17.263	14 456.8	COL every 3 yr	480.2	7.575	5592.9
DCBE every 5 yr	542.3	17.256	…	DCBE every 5 yr	563.4	7.562	…
SIG every 5 yr	542.4	17.255	…	SIG every 5 yr	571.8	7.560	…
COL every 3 yr	554.4	17.265	38 876.8	No screening	632.2	7.544	…
FOBT every 2 yr	810.0	17.252	…	FOBT every 2 yr	735.2	7.557	…
FOBT every 1 yr	1130.9	17.257	…	FOBT every 1 yr	842.3	7.564	…

COL: Colonoscopy; SIG: Sigmoidoscopy; DCBE: Double contrast barium enema; FOBT: Fecal occult blood test. Ellipse indicates no data (incremental CR ratios not calculated for these strategies because they were dominated).

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

²Incremental CE ratio (dollar/year) = Incremental cost per person/incremental years of life gained.

Table 3 Two-way sensitivity analysis by changing variables of index cancer such as 5-yr survival rate of first cancer and relative risk of colorectal cancer in Korean male cancer survivors

Relative risk of colorectal cancer in cancer survivor compared with that in general population	5-yr survival of index cancer = 20%				5-yr survival of index cancer = 40%				5-yr survival of index cancer = 80%
	Non-dominated strategy	Lifetime cost per person (dollar)1	Life expectancy (yr)	Incremental C/E2 (dollar)1 per life-year gained	Non-dominated strategy	Lifetime cost per person (dollar)1	Life expectancy (yr)	Incremental C/E2 (dollar)1 per life-year gained	Non-dominated strategy	Lifetime cost per person (dollar)1	Life expectancy (yr)	Incremental C/E2 (dollar)1 per life-year gained
5	COL5	329.0	4.512		COL5	532.5	7.567		COL5	957.9	13.829
	COL3	339.2	4.514	4921.7	COL3	542.2	7.571	2634.4	COL3	962.6	13.836	658.2
4	COL5	306.7	4.516		COL5	463.5	7.572		COL10	826.0	13.837
	COL3	329.0	4.517	18 078.3	COL3	480.2	7.575	5592.9	COL5	831.1	13.843	835.2
									COL3	879.7	13.847	11 508.2
3	COL10	266.6	4.517		COL10	401.4	7.576		COL10	682.9	13.847
	COL5	270.3	4.518	2685.2	COL5	409.6	7.579	3365.6	COL5	701.9	13.851	4104.9
	COL3	295.5	4.519	27 126	COL3	447.3	7.580	22 760.2	COL3	761.9	13.854	18 922.1
2	No screening	185.4	4.512		COL10	324.4	7.582		COL10	533.5	13.857
	COL10	224.5	4.52	4912	COL5	340.1	7.583	9506.4	COL5	566.7	13.860	10 725.2
	COL5	232.3	4.521	8378.3	COL3	383.7	7.584	39 469.5	COL3	638.6	13.862	34 075.6
	COL3	260.4	4.522	45 556.4
1	No screening	96.1	4.519		No screening	175.9	7.580		No screening	342.6	13.853
	COL10	180.5	4.523	20 568.2	COL10	244.0	7.587	9196.3	COL10	377.2	13.867	2424.5
	COL5	192.4	4.524	25 817.6	COL5	267.2	7.588	28 343.9	COL5	425.1	13.869	31 064.6
	COL3	223.5	4.524	103 111.0	COL3	316.8	7.589	91 808.0	COL3	509.3	13.870	81 681.8

COL10: Colonoscopy every 10 years; COL5: Colonoscopy every 5 years; COL3: Colonoscopy every 3 years; Dominated strategy is a strategy that is more or equally costly and less effective than a competing strategy.

¹Exchange rate, 955 Korean won for one US dollar in 2006;

²Incremental CE ratio (dollar/year) = Incremental cost per person/Incremental years of life gained.

Table 4 Two-way sensitivity analysis on cost-effectiveness of 2nd primary colorectal cancer screening by compliance of screening and age of Korean male cancer survivors for starting screening

Age for starting screening	Compliance of 2nd colorectal cancer screening = 60%				Compliance of 2nd colorectal cancer screening = 80%				Compliance of 2nd colorectal cancer screening = 100%
	Non-dominated strategy	Lifetime cost per person (dollar)1	Life expectancy (yr)	Incremental C/E2 (dollar)1 per life-year gained	Non-dominated strategy	Lifetime cost per person (dollar)1	Life expectancy (yr)	Incremental C/E2 (dollar)1 per life-year gained	Non-dominated strategy	Lifetime cost per person (dollar)1	Life expectancy (yr)	Incremental C/E2 (dollar)1 per life-year gained
40	COL5	370.0	8.633		COL10	341.0	8.326		COL10	352.2	8.328
	COL3	388.9	8.636	7584.1	COL5	343.7	8.329	872.5	COL5	369.2	8.330	7375.9
					COL3	383.7	8.330	26 483.2	COL3	424.1	8.331	50 842.3
50	COL3	479.2	7.665		COL5	463.5	7.572		COL10	475.0	7.571
					COL3	480.2	7.575	5592.9	COL5	476.0	7.574	330.8
									COL3	508.1	7.577	14 571.1
60	COL3	528.3	7.668		COL3	522.1	6.057		COL5	519.5	6.057
									COL3	529.5	6.059	4186.7

COL10: Colonoscopy every 10 years; COL5: Colonoscopy every 5 years; COL3: Colonoscopy every 3 years. Dominated strategy is a strategy that is more or equally costly and less effective than a competing strategy.

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

²Incremental CE ratio (dollar/year) = Incremental cost per person/Incremental years of life gained.