Custom Search by Tirgan.com

Home    Content    services

Gastrointestinal Stromal Tumors (GIST)

Gastrointestinal stromal tumor (GIST) refers to a distinct group of tumors that originate in gastrointestinal (GI) tract (60% in stomach, 30% small intestine, 10% elsewhere). GISTs include most tumors that were previously leiomyoma, cellular leiomyoma, leiomyoblastoma, and leiomyosarcoma, mostly thought to be tumors of smooth muscles of GI tract . Gastrointestinal stromal tumors (GIST) are uncommon tumors that arise in the wall of the GI tract with about 150 new cases diagnosed in the United States each year.

The most interesting findings in this group of tumors is that they have a unique molecular marker, known as  c-kit (CD117).  This maker is an indicator of responsiveness to treatment with Gleevec.  These tumors may be of variable sizes at the time of diagnosis and can range from a few millimeters to more than 30 cm. Although larger tumors have a higher rate of malignancy, size does not predict the prognosis and small GISTs have been known to behave in a malignant fashion.  Malignancy is characterized by local invasion and metastases, particularly to the liver. 

The occurrence of this disease is approximately equal in both sexes and all races in United States.

Signs and Symptoms

Patients may not manifest any signs at early stages of this illness. GISTs usually cause symptoms as a result of their size or tendency to ulcerate and bleed. it can cause any of the following problems:

• Abdominal pain

• Enlargement of Liver

• GI Bleeding

• Weight loss

• Palpable abdominal tumor mass

Diagnosis

The diagnosis is often suspected with a radiological examination of abdomen.  The confirmation of the diagnosis is made by pathological examination of the tumor and detection of c-kit (CD117) molecular marker.

Staging

• Stage I, localized or locally advanced disease,

• Stage II, patients who present with perforated tumors at diagnosis,

• Stage III, patients with multiple primary lesions or distant metastases at diagnosis,

Treatment

Almost all patients with this disease are treated with surgery to remove the tumor.  Complete resection was achieved in about two thirds of the patients. Despite surgery, most patients need further Adjuvant Therapy with Radiation therapy along with Gleevec, which is indicated for treatment of patients with KIT (CD117) positive unresectable and/or metastatic malignant tumors.

Prognosis:

Overall, patients with localized and small size tumor have a better prognosis.  Regardless of the stage at presentation, survival rates with malignant GISTs are 69% at 1 year, 38-44% at 3 years, and 29-35% at 5 years. Average survival is about 60 months with localized disease, 19 months with metastatic disease, and 12 months with local recurrence.  There is a high rate or recurrence even after curative surgery.