Cost-benefit analysis of esophageal cancer endoscopic screening in high-risk areas of China

Table 1 Non-age-specific parameters

Parameters	Value	Parameters	Value	Parameters	Value1
Initial probability2		Transition probability-continued		Compliance of screening2	67% (30%-100%)
Normal	0.8895	SD/CIS	see Table 2	Sensitivity of endoscopy[6]	96% (92%-99%)
mD	0.0820	IC	see Table 2	Specificity of endoscopy[6]	90% (59%-100%)
MD	0.0180	INC		Screening cost (I$ per capita)2
SD/CIS	0.0090	Recovering to post-INC	0.7696	Direct cost	61.50 (37.00-119.00)
IC	0.0008	Relapsing to INC after treatment	0.2304	Indirect cost	8.31 (8.09-8.53)
SC	0.0005	After treatment4		Treatment cost (I$ per capita)[24]2
INC	0.0002	Post-SD/CIS		Direct cost
Transition probability[9,16-21]2,3		Recovering to normal	0.9950	SD/CIS	1292 (1114-1565)
Normal		Relapsing to SD/CIS	0.0050	IC	1292 (1114-1565)
Remaining normal	0.9760	Post-IC		SC	1818 (1519-2799)
Progression to mD	0.0240	Remaining post-IC	0.9450	INC-screening group	2767 (2332-4031)
mD		Relapsing to IC	0.0500	INC-control group	4888 (4333-6396)
Regression to normal	0.0500	Relapsing and progression to SC	0.0050	Indirect cost
Remaining mD	0.9000	Post-SC		SD/CIS	1654 (1341-1968)
Progression to MD	0.0500	Remaining post-SC	0.8500	IC	1654 (1341-1968)
MD		Relapsing to SC	0.0500	SC	3369 (2872-3866)
Regression to mD	0.0800	Relapsing and progression to INC	0.1000	INC-screening group	3369 (2872-3866)
Remaining MD	0.8000	Post-INC (Same with “INC”)		INC-control group	5526 (4584-6466)
Progression to SD/CIS	0.1200	Death probability	see Table 2	Discount rate[12]5	3% (0%-6%)

mD: Mild dysplasia; MD: Moderate dysplasia; SD/CIS: Severe dysplasia/carcinoma in situ; IC: Intramucosal carcinoma; SC: Submucosal carcinoma (T₁N₀M₀); INC: Invasive carcinoma; I$: International dollar.

¹For compliance, sensitivity and specificity of endoscopy, screening and treatment costs, and discount rate, the numerals before and in the parenthesis denote the base case and ranges used in sensitivity analysis;

²Data were calculated in terms of the project called “Early Detection and Early Treatment of Esophageal Cancer in Demonstration Centers in China”;

³Data were collected from the death registry report of Linzhou County during 2004-2006s;

⁴Post-SD/CIS, post-IC, post-SC and post-INC represent the “health” condition after treatment of SD/CIS, IC, SC and INC;

⁵Costs and life years were discounted during the Markov cycles.

Table 2 Age-specific parameters

Parameters	Value
	40-yr	45-yr	50-yr	55-yr	60-yr	65-69-yr
Transition probability
SD/CIS
Regression to MD	0.17	0.15	0.14	0.12	0.11	0.09
Remaining SD/CIS	0.75	0.75	0.74	0.74	0.73	0.73
Progression to IC	0.08	0.10	0.12	0.14	0.16	0.18
IC
Remaining IC	0.60	0.50	0.40	0.20	0.15	0.13
Progression to SC	0.40	0.50	0.60	0.80	0.85	0.87
SC
Remaining SC	0.80	0.70	0.55	0.20	0.17	0.15
Progression to INC	0.20	0.30	0.45	0.80	0.83	0.85
Death probability
Non-esophageal-cancer mortality	0.002270	0.003073	0.007054	0.017061	0.019744	0.024105
All-cause mortality	0.002438	0.003383	0.007967	0.019559	0.021985	0.027370
Case fatality rate of esophageal cancer	0.581700	0.581700	0.581700	0.581700	0.581700	0.581700

MD: Moderate dysplasia; SD/CIS: Severe dysplasia/carcinoma in situ; IC: Intramucosal carcinoma; SC: Submucosal carcinoma (T₁N₀M₀); INC: Invasive carcinoma.

Table 3 Estimated epidemiological and economic effects for each strategy with 100 000 people under baseline assumptions

Screening strategies t(y)nf/ t(y)f1	Life years	Life years saved (LYS)	Costs (I$)	ICER (I$/LYS)	Benefit (I$)	NPV (I$ )	BCR
Non-screening	1 811 125	-	46 354 958	D	-	-	-
Once(40)nf	1 813 664	2539	39 133 890	D	62 964 854	23 830 964	1.61
Once(45)nf	1 814 180	3055	38 213 022	D	66 340 477	28 127 455	1.74
Once(50)nf	1 814 634	3509	36 989 316	D	69 310 502	32 321 186	1.87
Once(40)f	1 817 922	6797	38 007 700	D	90 820 285	52 812 585	2.39
Once(45)f	1 818 783	7658	36 792 906	ED	96 452 865	59 659 959	2.62
Once(50)f	1 817 966	6841	36 117 125	/	91 108 128	54 991 003	2.52
Twice(40)f	1 822 516	11 391	39 532 080	940	120 873 795	81 341 715	3.06
Twice(45)f	1 821 595	10 470	38 665 956	702	114 848 701	76 182 745	2.97
Twice(50)f	1 819 124	7999	38 261 433	ED	98 683 654	60 422 221	2.58
Thrice(40)f	1 823 528	12 403	41 665 346	2108	127 494 203	85 828 857	3.06
Thrice(45)f	1 821 827	10 702	40 775 616	D	116 366 423	75 590 807	2.85
Six times(40)f	1 826 509	15 384	48 042 566	2139	146 995 621	98 953 055	3.06

I$: International dollar. ICER means incremental cost-effectiveness ratio, which is defined as the additional cost of a specific strategy divided by its additional life years, as compared with the next-less-expensive strategy. D means dominated, e.g., the screening strategy is more expensive and less effective than another strategy. ED means extended dominated, e.g., if a screening strategy has a higher ICER than the next more costly, more effective strategy, it is extendedly dominated by that more cost-effective strategy. NPV: Net present value; BCR: Benefit-cost ratio.

¹t(y)nf/t(y)f: t denotes the frequencies of screening, y represents the starting age of screening, nf means we do not follow up the mild dysplasia and moderate dysplasia cases diagnosed by screening, and f means the mild dysplasia and moderate dysplasia cases diagnosed by screening are followed up every five and three years, respectively. For twice and thrice screening strategies in the lifetime, the screening intervals were 10 years; for the six times screening strategy in the lifetime, the screening intervals were five years. “-”: Life years saved, benefits, NPVs and BCRs of screening strategies were all calculated by comparing with non-screening group, accordingly, those are null for non-screening group; “/”: As the cheapest strategy, the ICER is null for the once(50)f-strategy.