Management of gastrointestinal stromal tumors: from diagnosis to treatment.

Gastrointestinal stromal tumours (GIST) are the most common mesenchymal tumours of the digestive tract. Most gastrointestinal soft tissue neoplasms, previously classified as leiomyomas, schwannomas, leiomyoblastomas or leiomyosarcomas, are today classified as GIST on the basis of molecular and immunohistological features. They originate from gastrointestinal pacemaker cells and are characterised by over-expression of the tyrosine kinase receptor KIT. Overall 5-year survival after surgical resection of GIST is approximately 60%. However, these tumours span a wide clinical spectrum from benign to highly malignant. Prognostic factors have recently been identified for GIST and include tumour size, mitotic rate and other minor factors. At present, surgery is the standard treatment for primary resectable GIST. Benign GIST have an excellent prognosis after primary surgical treatment, with over 90% 5-year survival. While recurrent or malignant GIST, which are resistant to radiotherapy and chemotherapy, had until recently an extremely poor prognosis even after surgical resection, with median survival of 12 months. The development of a tyrosine kinase inhibitor has changed the management of unresectable malignant cases. This new tyrosine kinase inhibitor, imatinib mesylate, which inhibits the c-kit receptor, has proved highly effective against GIST and has improved survival in metastatic GIST. This paper reviews the literature and our experience of GIST, including: diagnosis, pathology, treatment and prognosis.