What is Gastrointestinal Stromal Tumours (GIST)
Gastrointestinal stromal tumours (GISTs) are the most common mesenchymal tumours of the gastrointestinal (GI) tract. Before the current definition of GIST evolved, GISTs were classified as benign or malignant smooth muscle tumours including true smooth muscle tumours (leiomyomas, leiomyoblastomas, leiomyosarcomas) and neuronal tumours (schwannomas)1,2.
Patients with GIST may be asymptomatic (31%) or symptomatic.3 Asymptomatic GISTs can be discovered incidentally during endoscopy or laparoscopy as well as during computed tomography (CT)4. Symptomatic GIST patients may present with a range of symptoms associated with the location of the tumour, growth pattern, and size.
The diagnosis if GIST
The diagnosis of GIST relies on standard histologic examination and immunohistochemical analysis of several markers, including KIT. Equivocal cases should be submitted to a central review by an expert in sarcoma pathology, experienced in the diagnosis of GIST.
Incidence of GIST
GIST is now recognised as having a much higher incidence than previously thought. Under the current, widely accepted definition of GIST as a distinct molecular and pathologic entity, the incidence of GIST is in the range of 10-20 cases per million persons per year 5-8. The prevalence of GIST in a population-based study was estimated to be 129 cases per million persons. GIST tumours occur at a median age of 60 years and are slightly more predominant in men than women9
1. Fletcher CDM, Berman JJ, Gorstein F, et al. Diagnosis of gastrointestinal stromal tumors: a consensus approach. Hum Pathol. 2002;33:459-465.
2. Connolly EM, Gaffney E, Reynolds JV. Gastrointestinal stromal tumours,Br J Surg. 2003;90:1178-1186.
3. Kindblom LG. Gastrointestinal stromal tumors: diagnosis, epidemiology, prognosis. Available at: www.asco.org. Accessed July 13, 2007.
4. Joensuu H, Fletcher C, Dimitrijevic S, Silberman S, Roberts P, Demetri G. Management of malignant gastrointestinal stromal tumours. Lancet Oncol. 2002;3:655-664.
5.. Goettsch WG, Bos SD, Breekveldt-Postma N, Casparie M, Herings RM, Hogendoorn PC. Incidence of gastrointestinal stromal tumours is underestimated: results of a nation-wide study. Eur J Cancer. 2005;41:2868-2872.
6. Joensuu H. Current perspectives on the epidemiology of gastrointestinal stromal tumours. Eur J Cancer. 2006;4(suppl 1):4-9.
7. Blay JY, Bonvalot S, Casali P, et al. Consensus meeting for the management of gastrointestinal stromal tumors. Report of the GIST Consensus Conference of 20-21 March 2004, under the auspices of European Society for Medical Oncology. Ann Oncol. 2005;16:566-578.
8. Miettinen M, Lasota J. Gastrointestinal stromal tumors--definition, clinical, histological, immunohistochemical, and molecular genetic features and differential diagnosis. Virchows Arch. 2001;438:1-12.
9. Nilsson B, Bumming P, Meis-Kindblom JM, et al. Gastrointestinal stromal tumors: The incidence, prevalence, clinical course, and prognostication in the preimatinib mesylate era. Cancer. 2005;103:821-829