Prevalence of gastrointestinal stromal tumour (GIST) in the United Kingdom at different therapeutic lines: an epidemiologic model

Table 1 Model parameters

Parameter	Base-case Value (SE)^$	Min-max range for one-way SA^$	Distribution for PSA^$	References
GIST ^$ incidence (Γ) in person-years	1.053/100000 (SE = 0.139/100000)	0.52/100000 to 1.50/100000	Gamma	[3–5, 8, 11, 19, 21, 31, 32]
Proportion of resectable GIST (p)	0.8 (SE = 0.05)	0.50 – 0.90	Beta	[4, 9, 11–13, 15, 33]
Post-resection GIST TTT ^$ (γ ₂ )*	0.0464 (SE = 0.0025)	0.029 – 0.186	Gamma	[34–38]
Imatinib-treated GIST TTT (γ ₃ )*	0.351 (SE = 0.103)	0.205 – 0.645	Gamma	[14, 39–44]
Sunitinib-treated GIST TTT (γ ₄ )*	0.974 (SE = 0.085)	0.533 – 1.435	Gamma	[45–48]
Third-line treatment-eligible GIST survival (γ ₅ )*	0.904 (SE = 0.10)	0.439 – 1.066	Gamma	[24, 25, 49–53]
Yearly background mortality	0.0314 (SE = 0.0023)	0.0269 – 0.0359	Gamma	[20]

^$ GIST = gastrointestinal stromal tumour; SE = standard error; SA = sensitivity analysis; PSA = probabilistic sensitivity analysis; TTT = time to transition;
*Yearly rate assuming patients’ survival followed an exponential distribution.

ISSN: 1471-2407