Is Gastrointestinal Stromal Tumor Cancerous?

Though GISTs can begin anywhere throughout the gastrointestinal (GI) tract:

• 60 percent of cases of GISTs begin in the stomach, and
• 35 percent of the other types begin in the small intestine.

A tiny percentage of GISTs begin outside the GI tract, such as the omentum (fatty tissue that hangs over the abdominal organs) or the peritoneum (the layer that lines the walls and organs of the abdomen).

Some GISTs appear to be significantly more potent than others at spreading to other sections of the body. Certain indicators are examined by doctors to determine if a GIST is likely to develop and spread quickly.

The average five-year survival rate of GIST is 83 percent. However, survival rates for this type of tumor are affected by several factors, including the tumor's biological features, the type of treatment administered, and the risk of recurrence following treatment.

• If cancer is localized to the primary organ, the five-year survival rate is 93 percent.
• If cancer has spread to nearby tissues or organs, the five-year survival rate is 88 percent.
• If cancer has gone to a distant part of the body when it is initially identified, the five-year survival rate is 55 percent.

People with early-stage gastrointestinal stromal tumors (GISTs) frequently do not exhibit any signs of the condition. The majority of GISTs are discovered after you acquire symptoms, which may include:

1. Discomfort or pain in the abdomen
2. Nausea and vomiting
3. Diarrhea
4. Constipation
5. Having blood in your stools or vomit
6. Anemia (low red blood cell count) induced by bleeding
7. Fatigue
8. Muscle cramps
9. Feeling satisfied with only a tiny quantity of food (early satiety)
10. Appetite loss or weight loss
11. Changes in the skin or hair
12. A palpable bulge or tumor in the abdomen

Many of the symptoms may be the result of other health issues; however, you should still consult your doctor. Only a doctor can tell you whether you have cancer or not.

The exact cause of gastrointestinal stromal tumors (GISTs) is unknown. However, researchers believe that changes in the DNA of cells cause the development of these tumors.

There is no known specific reason for changes in DNA, but it is known that a gene mutation responsible for the development of GISTs runs in the family. Although, this is seen only in a small group of families, and not all GISTs are inherited.

Risk factors

• Age: Mostly seen in older adults, older than 40 years.
• Sex: More males are affected than females.
• Family history of GISTs
• Associated with syndromes, SUCH AS Carney-Stratakis syndrome and Carney triad
• History of neurofibromatosis type I

Because gastrointestinal stromal tumors (GISTs) do not have specific symptoms, they are discovered by chance during the evaluation of a patient for general gastrointestinal symptoms. Therefore, it is highly necessary to pay close attention to the clinical signs and rule out GIST.

Both imaging and endoscopic techniques are used to diagnose GISTs.

• Endoscopy: Endoscopic tests allow the doctor to see the lining of the upper gastrointestinal system, including the esophagus, stomach, and duodenum, using an endoscope (a flexible tube with a light and a tiny camera connected to it). The tube is passed down through the throat for examination.
• Computed tomography scans and magnetic resonance imaging: These imaging tests are performed to look for any abnormal growth. They can reveal the location of the tumor and whether it has spread.
• Biopsy: Cancer can only be confirmed by a biopsy. Small sections of tissue are removed from the tumor and tested for cancer cells under a microscope. During the endoscopy, a doctor may obtain biopsy samples. In other circumstances, a sample could be obtained by inserting a thin, hollow needle through the skin and into the tumor, or a sample could be extracted during surgery.

The staging of cancer determines the seriousness of the illness, as well as the treatment. 

Usually, cancers are categorized into four stages; the higher the stage, the more severe the development of cancer. The prognosis, treatment, and survival rate depend on the stage of cancer.

The American Joint Committee on Cancer’s tumor (T), nodes (N), and metastases (M) system is the most often used staging method for gastrointestinal stromal tumors (GISTs). The most recent version is effective as of 2018. This staging approach is based on four important factors.

1. Size of the primary tumor
   • TX: Primary tumor cannot be assessed.
   • T0: No evidence of primary tumor.
   • T1: Tumor size is less than or equal to 2 cm.
   • T2: Tumor size is more than 2 cm but less than 5 cm.
   • T3: Tumor size is more than 5 cm but less than 10 cm.
   • T4: Tumor size is more than 10 cm.
2. Involvement of regional lymph nodes
   • N0: Regional lymph node metastasis is absent, or lymph node status is unknown.
   • N1: Regional lymph node metastasis is present.
3. Distant metastasis
   • M0: Distant metastasis is absent.
   • M1: Distant metastasis is seen.
4. Mitotic rate
   • Low
   • High

The staging for GIST is of two different groups depending on the origin of the tumor.

A gastrointestinal stromal tumor (GIST) develops differently in everyone. The size and location of the tumor, as well as the rate at which it develops, are crucial factors. The chance of cancer spreading to other places of the body (metastasis) varies greatly as well.

Sometimes, it is difficult to distinguish between benign (noncancerous) and malignant growth (cancer). However, it has been established that all GISTs are potentially a risk for malignancy development.

Even a small, slow-growing tumor can spread in some situations. The tumor's location appears to influence its behavior. When a GIST metastasizes, it generally spreads to the liver or the abdominal wall lining.

Surgery

Surgery is considered in most cases. The objective of surgery is the complete removal of the tumor. However, surgery alone may not be effective for a bigger GIST or a GIST that has already spread. A big tumor may be treated with targeted treatment to shrink it sufficiently to be removed surgically.

Targeted therapy

These drugs target components of cancer cells. GIST is treated with targeted treatment medications, such as imatinib, regorafenib, avapritinib, and sunitinib. Though targeted therapy sounds similar to chemotherapy, the targeted therapy drugs work differently. Targeted therapy is done before surgery to shrink large tumors.

Ablation of gastrointestinal tumors

Tumor ablation is the destruction of tumors using severe heat or cold or chemicals. It can occasionally be utilized to eradicate GISTs that have migrated to the liver as a few tiny tumors. Because ablation frequently kills part of the normal tissue around the tumor, it may not be appropriate to treat tumors near vital organs, such as major blood arteries, the diaphragm, or major ducts in the liver.

4 types of ablations

1. Cryotherapy: A thin metal probe to freeze a tumor and eradicate it. This approach occasionally necessitates general anesthesia.
2. Radiofrequency ablation (RFA): A technique that employs high-energy radio waves to burn the tumor and kill cancer cells.
3. Microwave thermotherapy: Microwaves are sent through a probe inserted in the tumor to heat and kill cancer cells.
4. Ethanol ablation: Involves injecting concentrated alcohol directly into the tumor to destroy cancer cells.

Chemotherapy

Chemo is a broad term for certain medications that act by destroying rapidly developing cells everywhere in the body, including cancer cells. Chemotherapy is the use of medications to treat cancer. These medications are frequently injected into a vein (intravenous route) or administered orally. They penetrate the circulation and propagate throughout the body. 

Chemotherapy is potentially effective for tumors that have gone beyond the organ in which they originated. The use of chemotherapy for GIST is rare.

Radiation therapy

Radiation therapy uses high-energy X-rays to kill cancer cells. Though radiation therapy has no role in GIST, it is used to alleviate bone pain in some cases.

Though surgically the tumor is removed, sometimes, it is not possible to remove the complete tumor, or cancer cells are not killed completed even after treatment with various methods. In such conditions, continuous treatment with targeted therapy is done to keep cancer from growing and alleviate symptoms.

You are required to follow up with your doctor regularly to know if you are cancer-free or present with recurrence. You must follow all the instructions given by your doctor and make necessary lifestyle changes as advised.