Societal cost-effectiveness analysis of the 21-gene assay in estrogen-receptor–positive, lymph-node–negative early-stage breast cancer in Japan

Table 2 Model inputs

Parameter	Mean	Sensitivity analysis		Source
Parameter	Mean	Low	High	Source
Baseline recurrence risk by 21-gene assay risk group
Japan
Low-risk	3.3%	1.1%	10.0%	[17]
Intermediate-risk	0.0%	0.0%	0.0%	[17]
High-risk	24.8%	15.7%	37.8%	[17]
US and UK
Low-risk	5.4%	3.6%	8.5%	[11, 14]
Intermediate-risk	13.7%	8.6%	20.0%	[11, 14]
High-risk	29.2%	21.6%	37.2%	[11, 14]
Relative reduction of recurrence with aCT by 21-gene assay risk group
Low-risk	0%	0%	54%	[15]
Intermediate-risk	39%	0%	76%	[15]
High-risk	74%	47%	87%	[15]
Costs*
21-gene assay	¥350,000 ($3,500)	¥262,500	¥437,500	List price
Associated with aCT
Drugs	¥561,813 ($5,618)	¥280,907	¥1,500,000	St. Luke’s Hospital (Tokyo, Japan)
Adverse events	¥170,831 ($1,708)	¥85,416	¥256,247	St. Luke’s Hospital (Tokyo, Japan), [24]
Patient time and transportation	¥68,500 ($685)	¥34,250	¥102,750	St. Luke’s Hospital (Tokyo, Japan)
Surveillance (2 visits/year)	¥25,416 ($254)	¥12,708	¥38,124	[23]
Per recurrence per year	¥2,405,924 ($24,059)	¥1,202,962	¥3,608,886	[22]
Quality of life
No recurrence, no aCT	0.98	0.78	1.00	[23]
Progression	0.30	0.24	0.36	[26, 27]
QALY tariff of aCT	0.53	0.43	0.64	[23, 24, 28]
Other assumptions
Age	49.8	35	75	St. Luke’s Hospital (Tokyo, Japan)
Annual mortality risk after progression	40%	20%	60%	[22, 23]
Time horizon, years	Lifetime			ISPOR guidelines

Abbreviations: ¥, JPY Japanese Yen, $, USD United States Dollar, aCT adjuvant chemotherapy, QALY quality-adjusted–life-year, ISPOR International Society For Pharmacoeconomics and Outcomes Research.
A 3% time preference discount rate was applied in the basecase scenario (lower bound, 1%; upper bound, 5%) [21].
*Per patient on average. Reported in 2013 currency. Conversion rate is 100 JPY per 1 USD.

ISSN: 1472-6963