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

• Published in: BMC cancer 2014-05, Vol.14 (1), p.364-364, Article 364
• Main Authors: Starczewska Amelio, Justyna M, Cid Ruzafa, Javier, Desai, Kamal, Tzivelekis, Spiros, Muston, Dominic, Khalid, Javaria Mona, Ashman, Philip, Maguire, Andrew
• Format: Article
• Language: English
• Subjects: Age; Antineoplastic Agents - therapeutic use; Benzamides - therapeutic use; Cancer; Cancer therapies; Confidence intervals; Epidemiology; Estimates; Gastrointestinal Stromal Tumors - drug therapy; Gastrointestinal Stromal Tumors - epidemiology; Gastrointestinal Stromal Tumors - mortality; Gastrointestinal Stromal Tumors - secondary; Humans; Imatinib Mesylate; Incidence; Indoles - therapeutic use; Medical treatment; Metastasis; Models, Statistical; Mortality; Parameter estimation; Piperazines - therapeutic use; Population; Prevalence; Protein Kinase Inhibitors - therapeutic use; Pyrimidines - therapeutic use; Pyrroles - therapeutic use; Rare Diseases - drug therapy; Rare Diseases - epidemiology; Rare Diseases - mortality; Registries; Studies; Sunitinib; Treatment Failure; Tumors; United Kingdom - epidemiology; Validity
• ISSN: 1471-2407; 1471-2407
• DOI: 10.1186/1471-2407-14-364

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.