GIST

Origin and Causes

Gastrointestinal Stromal Tumor (GIST) accounts for 1% of gastrointestinal tract cancers. The annual incidence is around 11-19.6 cases per million per year. The average age of diagnosis for a GIST is typically around 60 years. The majority of GIST patients have no identifiable cause. A minority of cases can occur in the context of hereditary genetic diseases such as neurofibromatosis.

 

Symptoms and Signs

More than 80% of GISTs will locate in the stomach, jejunum, ileum, duodenum, or colon and rectum. GIST patients may feel an abdominal mass, have bleeding in their digestive tract, or develop abdominal pain. Some patients may develop metastases which are mostly located in the liver or abdominal cavity.

 

Diagnosis

When a GIST is suspected, the initial evaluation includes either a CT-Scan or MRI. The diagnosis is made by biopsy of the suspected area through endoscopy of the stomach (EGD) or intestine (colonoscopy). The final diagnosis of GIST is made in pathology. Molecular studies may be performed to better specify the type of GIST. The majority of GISTs are defined by mutations in the KIT and PDFGRA genes.

 

Treatment

When a GIST is localized, the treatment of choice is surgery to remove it all. Sometimes, in the case of very small GISTs, simple observation may be offered. In some cases, treatment with Imatinib (an oral medication) may be necessary before or after surgery.

 

In the case of metastases being found, surgery is no longer possible. The goal of treatment is to control symptoms and the progression of the disease. The preferred agents for GIST treatment are Imatinib, sunitinib, regorafenib, and ripretinib. Clinical trials may also be explored.

 

Follow-up

After surgery, GIST patients will be closely monitored due to the risk of recurrence (when cancer returns). CT-Scans at different intervals will be performed.

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