Prevalence of gastrointestinal stromal tumour (GIST) in the United Kingdom at different therapeutic lines: an epidemiologic model
1 Health Economics and Epidemiology, Evidera, Metro Building, 6th floor, No.1 Butterwick, London W6 8DL, UK
2 Global Market Access, Bayer Pharma AG, Berlin S157, 03, 305, Germany
3 Health Economics, Bayer plc, Strawberry Hill, Newbury RG14 1JA, UK
BMC Cancer 2014, 14:364 doi:10.1186/1471-2407-14-364Published: 24 May 2014
The prevalence of patients with gastrointestinal stromal tumourgst (GIST) who fail currently available treatments imatinib and sunitinib (third-line treatment-eligible GIST) is unknown, but is expected to be below an ultra-orphan disease threshold of 2/100,000 population used in England and Wales. Our study was designed to estimate the prevalence and absolute number of UK patients with unresectable/metastatic GIST at first-, second- and eventually third-line treatment.
Our open population model estimates the probability that the prevalence of UK third-line treatment-eligible GIST patients will remain under the ultra-orphan disease threshold. Model parameters for incidence, proportion of unresectable/metastatic disease and survival estimates for GIST patients were obtained from a targeted literature review and a UK cancer register. The robustness of the results was checked through differing scenarios taking extreme values of the input parameters.
The base-case scenario estimated a prevalence of third-line treatment-eligible GIST of 1/100,000 and a prevalence count of 598 with a 99.9% likelihood of being below the ultra-orphan disease threshold. The extreme scenarios, one-way and probabilistic sensitivity analyses and threshold analysis confirmed the robustness of these results.
The prevalence of third-line treatment-eligible GIST is very low and highly likely below the ultra-orphan disease threshold.