Gastrointestinal Stromal Tumor (GIST)

Gastrointestinal Stromal Tumor (GIST)

What is the Gastrointestinal Tract?

The gastrointestinal (GI) tract, also known as the digestive tract, includes the following organs:

• Esophagus

• Stomach

• Gallbladder, bile ducts

• Liver

• Pancreas

• Small intestine

• Large intestine (colon)

• Rectum

• Anus

• Intestinal lining

The digestive tract plays a key role in digesting food and eliminating waste. When food is swallowed, the esophagus uses muscles to push the food into the stomach. The stomach produces gastric juices that help digest the food, which then moves to the small intestine, where the digestion process continues. Waste material is moved to the large intestine and then to the rectum and anus for elimination.

What is Gastrointestinal Stromal Tumor (GIST)?

GIST is a tumor that forms when healthy cells in the digestive tract grow uncontrollably, forming a mass. This mass can either be cancerous or non-cancerous (benign). GIST can begin anywhere in the GI tract, but unlike other cancers, GIST is a type of soft tissue sarcoma, meaning it starts in the soft tissues that support and connect the body.

Statistics

GIST is rare, accounting for only about 1% of all gastrointestinal cancers. While there is no exact data for India, in the United States, around 4,000 to 6,000 cases of GIST are diagnosed each year. Of these, 60% originate in the stomach, and 35% in the small intestine.

Survival Rate

According to U.S. data, the 5-year survival rate for GIST is approximately 85%.

Risk Factors

A risk factor is anything that increases the likelihood of developing cancer. While risk factors influence cancer development, they do not directly cause it. Risk factors for GIST include:

• Age: GIST typically begins after age 50.

• Gender: It is more common in men than women.

• Genetic Conditions: Conditions like Neurofibromatosis type 1 and Carney-Stratakis dyad increase the likelihood of GIST.

Symptoms

Most people with GIST do not have symptoms. However, possible symptoms include:

• Abdominal pain or discomfort

• Lump in the abdomen

• Nausea

• Vomiting

• Intestinal blockage

• Vomiting blood

• Blood in the stool (black stool)

• Fatigue

Diagnosis

• CT Scan

• Endoscopy: A thin, flexible tube with a light and camera is inserted through the mouth or nose into the esophagus to examine the GI tract. If suspicious areas are found, a biopsy may be taken.

• Capsule Endoscopy: A small capsule containing a camera and light is swallowed, allowing detailed examination of the GI tract.

• MRI

• Biopsy: A small sample of tissue is removed from the suspicious area and examined under a microscope to confirm whether it is cancerous.

• PET CT

Treatment

1. Surgery: The primary treatment for GIST that hasn’t spread is surgery. During surgery, the tumor and some surrounding healthy tissue (margin) are removed.

2. Targeted Therapy: This treatment targets specific genes, proteins, or the environment of the cancer cells. Drugs like Imatinib, Sunitinib, Regorafenib, Avapritinib, and Ripretinib are used in GIST treatment.

3. Radiation Therapy: High-energy radiation is used to destroy cancer cells. It is delivered externally through a machine (external beam radiation therapy). Radiation is not commonly used as the primary treatment for GIST but may be used for palliative care.

GIST Follow-Up

After completing cancer treatment, regular follow-up tests are necessary to manage side effects and ensure the cancer does not return. Follow-up care typically includes regular physical examinations, blood tests, and imaging tests.

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