Gastrointestinal stromal tumor, or GIST, is a rare type of sarcoma that forms along the gastrointestinal tract, but mostly starts in the stomach or small intestine.
We often don’t know why certain people develop GIST. In some cases, though, risk factors can increase your chances of developing this disease. The primary risk factor for GIST is genetics, meaning that the cancer can run in families. Certain genetic syndromes may also be GIST risk factors, including:
- Neurofibromatosis type 1
- Carney triad
Most patients with GIST do not have any specific symptoms. GIST symptoms are common to a variety of different problems. Check with your doctor if you experience any of the following:
- Blood in your vomit or stool
- Severe stomach pain
- Painful swallowing
- Your stomach feels full even after eating just a small amount
To determine if you are suffering from a GIST tumor, as well as whether it is surgically removable, your surgical oncologist will perform a number of diagnostic tests, including:
- Medical history: We will review your symptoms and discuss your medical history, including illness and previous surgeries. We will also discuss whether anyone else in your family suffered from GIST.
- Physical examination: We will examine your carefully for signs of a GIST tumor.
- CT scan: This imaging test uses x-ray technology and computers to create a detailed picture of your gastrointestinal organs and tissues.
- MRI: This imaging test uses high powered magnets to create a picture of your gastrointestinal organs.
- Endoscopic ultrasound and biopsy: In this procedure, your surgeon creates an image of your gastrointestinal tract and removes tissues for a biopsy. A biopsy is a close examination of your tissue under a microscope that determines whether the tissue is cancerous.
In addition to diagnosing GIST, these tests can also help surgical oncologists learn whether your cancer is spreading to other parts of your body.
- Positron emission tomography (PET) scan: This imaging test can identify the presence of cancerous cells. Your doctor will inject a vein with radioactive glucose, and then follow it as it affects different types of cells. Cancerous cells look different than non-cancerous cells.
- Chest x-ray: This x-ray indicates whether cancer is spreading to the organs and bones in your chest.
Understanding Your GIST Diagnosis
It is important to discuss the results of your diagnostic tests with your surgical oncologist. We will make sure to explain everything to you. In particular, it’s important that you know about:
- Tumor size
- Mitotic count, or the number of abnormal cells visible under a microscope
- Tumor location
- c-KIT positivity, or whether you have a certain molecule that indicates a GIST tumor
- Tumor stage
- Whether you need targeted therapy before or after surgery
- What clinical trials are available
- What your chances of recurrence after surgery are
Armed with this information, your team of surgical oncologists can determine the most effective treatment options for your disease.
Treatment for GIST
Because GIST is so rare, few doctors have experience treating it. However, MedStar Georgetown University Hospital has become one of the country's major centers for the clinical study of GIST, and serves as a site for clinical trials that have revolutionized fighting the disease.
Surgery is the standard treatment, but not all GISTs can be removed. About a decade ago, patients diagnosed with recurrent or metastatic GIST had few treatment options or hope for survival. Today, the outlook is more promising.
Your treatment options for GIST depend on two factors:
- Whether a surgical procedure can remove your tumor
- Whether your tumor is spreading to other parts of your body
Depending on these factors, your specialist may recommend:
- Surgery : This is the prime option for GIST tumors that have not spread to other areas of the body. Surgical oncologists can completely remove the tumor, as well as surrounding tissue.
- Targeted therapy before surgery: This treatment uses special drugs to locate the tumor and destroy cancer cells. Targeted therapy can help shrink very large tumors so your surgeon can then remove them with surgery. Imatinib is the most commonly used targeted therapy for GIST.
- Targeted therapy after surgery: For some patients, we recommend targeted therapy after surgical removal of your GIST. To determine whether you need this treatment, we evaluate your pathology report, and factor in your tumor size and mitotic count. We also work closely with our multidisciplinary team of specialists to determine the best course of therapy for you.
Surgery is the standard treatment, but not all GISTs can be removed. Our clinical trials have studied the newest drugs available to target GIST, including imatinib, sunitinib and nilotinib. Our cancer team at was among the first to study imatinib, the first targeted therapy developed for GIST.
Please note: These drugs do not cure the disease, but they do help some tumors stop growing or shrink, which has extended the survival rate for patients with recurrent or metastatic GIST.
GIST Follow-Up Care
After your treatment, your team of physicians will follow your recovery closely. We will meet with you and repeat imaging and diagnostic tests to make sure the cancer is not returning or spreading.