Is a Gastrointestinal Stromal Tumor a Soft Tissue Sarcoma?

What are the common causes and risk factors of gastrointestinal stromal tumors?

Doctors do not know exactly what causes gastrointestinal stromal tumors (GISTs). Studies have identified a few possible causes or risk factors. GISTs begin when genetic mutations occur in certain genes, leading to uncontrolled cell growth.

Over time, this uncontrolled cell growth leads to the formation of tumors:

• People older than 50 years may be susceptible to GISTs.
• Men are at slightly higher risk.
• African Americans are more likely to develop GISTs.
• A rare inherited condition called primary familial GIST syndrome, caused by a genetic mutation puts family members at higher risk.
• About 75 to 80 percent of GIST cases have a mutation in the KIT gene, and in 5 to 10 percent of cases, there is a mutation in the PDGFRA gene. Less commonly, additional gene mutations are involved. Other genetic syndromes that could be associated with an increased risk of GIST are neurofibromatosis type I (von Recklinghausen disease) and Carney-Stratakis syndrome.

Currently, no preventable or non-genetic risk factors have been found, which means there is no way to prevent GISTs. Doctors may run tests to figure out the specific mutation involved because it helps determine the best course of treatment for GIST.

How are gastrointestinal stromal tumors diagnosed?

When the doctor suspects a GIST, they may recommend certain tests after a proper physical examination and medical history.

GIST is a rare type of cancer. The latest statistics estimate there are about 4,000 to 6,000 cases of GIST diagnosed in the United State each year. As with all cancers, not smoking, maintaining a healthy weight, and exercising are important for prevention.

What are the stages of gastrointestinal stromal tumors?

The treatment options for gastrointestinal stromal tumors (GISTs) usually depend on the patient’s age, underlying health conditions, and staging of the tumor.

Staging of GISTs

1. Stage I: The tumor has not spread to nearby lymph nodes, and the mitotic rate is low.
   • Stage IA: The tumor is no larger than 5 cm.
   • Stage IB: The tumor is larger than 5 cm but not larger than 10 cm.
2. Stage II: Cancer has not spread to nearby lymph nodes. In addition, the tumor is no larger than 5 cm and the mitotic rate is high, or the tumor is larger than 10 cm, and the mitotic rate is low.
3. Stage III: Cancer has not spread to the nearby lymph nodes, and the mitotic rate is high.
   • Stage IIIA: The tumor is larger than 5 cm but not larger than 10 cm. 
   • Stage IIIB: The tumor is larger than 10 cm.
4. Stage IV: Cancer has spread to nearby lymph nodes and distant parts of the body.

What are the treatment options for gastrointestinal stromal tumors?

Surgery

• Surgery is frequently the first-line treatment for cancers that are localized or can be resected (removed).
• Because these tumors are delicate and prone to rupture, the surgeon must have prior expertise in removing GIST tumors.
• GIST tumors can be surgically removed with an incision (cutting the skin) or using laparoscopic treatments depending on the size and location of the GIST tumor.

Targeted therapy

Many cancers that are associated with genetic abnormalities are especially sensitive to targeted treatment. These are drugs that precisely target an aberration identified on cancer cells. Tyrosine kinase inhibitors or multikinase inhibitors are the medications for targeted therapy.

• They work by inhibiting the action of a specific enzyme called tyrosine kinase.
• This enzyme is important in cell function and is active in cancer cells, increasing tumor development and progression.
• Imatinib is the major medication used to treat GIST. This drug is used after surgery and is usually taken for one to three years depending on the size and location of the tumor. The purpose of taking this drug after surgery is to prevent the tumor from returning.
• This medication can be used before surgery (called neoadjuvant therapy) to shrink the tumor and increase the possibility of complete removal of the tumor.

Interventional procedures

• Radiofrequency embolization or chemoembolization could be utilized to treat progressive GIST.
• Chemoembolization provides chemotherapy directly to the tumor via the artery that delivers blood to the tumor. The artery is subsequently stopped (embolized) to stop the flow of blood to the tumor.
• Radiofrequency embolization uses high-energy radio waves to heat the tumor and eliminate cancer cells.

Clinical trials

• Clinical research studies are available for almost every kind of cancer and at every stage of the disease.
• Clinical trials are intended to assess the efficacy of certain therapies and the optimal dose titration in the population. Trials are frequently designed to treat a certain stage of cancer, either as the initial kind of treatment provided or as a therapeutic alternative after previous treatments have failed.
• They can be used to assess drugs or therapies for cancer prevention, early detection, and side effect management.
• Clinical studies are critical to advancing the understanding of the illness. Many interesting novel medicines are presently being explored.
• Speak to the physician about taking part in clinical trials.

After surgery and while on medication maintenance therapy, the person will most likely be assessed by doctors for a physical exam, lab testing, and imaging (abdominal or pelvic computed tomography) every three to six months for the first five years and then, yearly.

Summary

• Gastrointestinal stromal tumors (GIST) have an estimated annual incidence of 1.5 per 100,000 people. This indicates that about 250 new GIST patients are diagnosed each year.
• Most GISTs occur without a defined cause, hence there are no evident hazards.
• Tumor development has a genetic origin in roughly five percent of patients.
• Smaller tumors (less than 2 cm) rarely produce symptoms and are usually detected by coincidence during another check-up.
• GIST that is larger in size might induce distinct symptoms.
• GISTs have different degrees of aggressiveness: malignant and benign.

The long-term prognosis is determined by several variables. The best results are predicted when the tumor size is small (less than 5 cm) and has extremely low mitotic activity. When the tumor has spread to other areas, the long-term prognosis is uncertain.

Most people with metastases have a survival duration of 10 to 20 months. Individuals without metastases have a five-year survival probability of 30 to 60 percent.