What are the other Names for this Condition? (Also known as/Synonyms)

• Gastric Gastrointestinal Stromal Tumor
• Gastric GIST
• GIST of Stomach

What is Gastrointestinal Stromal Tumor of Stomach? (Definition/Background Information)

• A gastrointestinal stromal tumor (GIST) is a type of tumor that occurs in the gastrointestinal tract. It can either be benign or malignant, depending on various characteristics. Most tumors occur randomly, while some originate due to a family history of the condition
• The most common location of this tumor is the stomach or small intestine. The origin of the tumor is uncertain. Some researchers believe that these tumors originate from a special type of cells that are present in the gastrointestinal tract, called the interstitial cells of Cajal (ICCs)
• Gastrointestinal Stromal Tumor of Stomach is a common tumor that forms anywhere in the stomach. Most of the small-sized tumors are discovered using imaging scans or endoscopy incidentally
• Gastrointestinal Stromal Tumor of Stomach may arise sporadically, or in the presence of an associated genetic disorder such as neurofibromatosis type 1, Carney triad, or Carney-Stratakis syndrome. In a majority though, the involvement of KIT and PDGFRA genes are noted (for both sporadic and familial cases)
• Small-sized tumors are not known to cause any significant symptoms, but larger tumors may result in abdominal discomfort and blood in stool. Malignant tumors are known to metastasize to the stomach, lungs, and other distant regions
• The standard treatment approach involves a surgical excision and removal of the entire tumor followed by chemotherapy. However, Gastrointestinal Stromal Tumor of Stomach outcome chiefly depends on the type of tumor (whether benign or malignant), size of the tumor, and cell activity (mitotic rate)

Who gets Gastrointestinal Stromal Tumor of Stomach? (Age and Sex Distribution)

• Among all the mesenchymal tumors in the gastrointestinal tract, Gastrointestinal Stromal Tumor of Stomach is the most common. About 60% of the tumors are noted in the stomach
• Some studies report tumor incidence as 10-15 cases per 100,000 population
• The tumor is mostly observed in older adults in the 60-65 year age group (median age period). In rare cases, it may be seen in children too
• Both males and females are affected and no specific preference for any gender is observed
• When the tumor is seen among younger populations, it may be seen in the background of an underlying genetic disorder. In such cases, females are affected more than males
• No racial or ethnic predilection is also noted

What are the Risk Factors for Gastrointestinal Stromal Tumor of Stomach? (Predisposing Factors)

• Currently, no definitive risk factors for Gastrointestinal Stromal Tumor of Stomach are known, when the tumors occur sporadically (in majority of the cases)
• However, in some cases, an association of the tumor with the following genetic disorders is noted:
  • Carney triad
  • Carney-Stratakis syndrome
  • Neurofibromatosis type 1 (NF1); in extremely rare cases

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Gastrointestinal Stromal Tumor of Stomach? (Etiology)

The cause of Gastrointestinal Stromal Tumors of Stomach is due to genetic mutations.

• Mutations in two specific genes account for a majority of the cases. Mutation in these genes, result in an uncontrolled growth of cells, leading to tumor formation
• It is estimated that 80% of such tumors are caused by a mutation in the KIT gene; around 10% of diagnosed cases, caused by a mutation in the PDGFRA gene. The reminder of the tumors occurs, due to mutation in certain other genes
• Children with neurofibromatosis type 1 do not show mutations in KIT or PDGFRA gene
• When Carney triad is present, the genetic factors are not very well-established

There are two types of gastrointestinal stromal tumors (GISTs) - sporadic tumors and familial tumors.

• Both, familial and sporadic tumors are caused by mutations in the KIT and PDGFRA genes. These genes are responsible for making proteins that are involved in cell growth and cell death. In a minority of the cases, the mutations are inherited from parents and in such cases, are called familial GIST
• In familial GIST, mutations are inherited in an autosomal dominant pattern, which means that only one copy of the mutated gene in each cell is enough to increase an individual’s chance of developing gastrointestinal stromal tumors
• In sporadic cases of GIST, there is usually a single tumor, whereas in familial type of GISTs, multiple tumors may occur

What are the Signs and Symptoms of Gastrointestinal Stromal Tumor of Stomach?

Some small-sized Gastrointestinal Stromal Tumors of Stomach may not cause any significant symptoms and are detected incidentally. In others, the following signs and symptoms may be noted:

• Feeling of abdominal discomfort
• If tumor bleeds or is ulcerated, then it may result in anemia (depending on whether the bleeding is acute/chronic)
• Obstruction of the stomach due to large tumors, may occur rarely
• The tumors may be located anywhere in the stomach
• Some tumors are very small, while some can grow to be very large masses
• In a majority of the cases, solitary tumors are observed; while, in familial cases, there may be multiple tumors with the GI tract (including tumors at other body locations)
• Malignant tumors may lead to weight loss, anemia (due to bleeding), pain in the upper abdominal region, and skin discoloration
• Some grow to involve the liver, spleen, and pancreas, including the large intestine

Urticaria pigmentosa (a skin disorder) is known to occur in patients with GISTs. In this disorder, the individual has skin lesions that are characterized by raised patches of itchy brownish skin.

How is Gastrointestinal Stromal Tumor of the Stomach Diagnosed?

A diagnosis of Gastrointestinal Stromal Tumor of Stomach would involve:

• Complete physical exam with evaluation of medical history
• Ultrasound scan of the stomach/abdomen: It is a non-invasive procedure that uses high frequency sound waves to produce real-time images
• Abdominal CT scan: It is a noninvasive procedure that provides more details of soft tissues, blood vessels, and internal organs
• Stool sample analysis
• Upper GI endoscopy: An endoscopic procedure is performed using an instrument called an endoscope, which consists of a thin tube and a camera. Using this technique, the radiologist can have a thorough examination of the insides of the gastrointestinal tract
• Chromoendoscopy can help detect small-sized tumors; small tumors can also be detected using narrow band imaging technique
• Endoscopic ultrasonography: During this procedure, fine needle aspiration biopsy (FNAB) can be performed on the affected area. This is good technique for tumor detection including tumor invasion parameters, and whether nearby lymph nodes are affected
• Vascular angiographic studies of the tumor
• Exploratory laparoscopy (diagnostic laparoscopy) may be required, if gastrointestinal symptoms are present. In this procedure, the abdomen is examined using a minimally-invasive technique, and a tissue biopsy and tissue for culture obtained

• Whole body PET scans to determine how far the cancer has spread to other organ systems

Although the above modalities can be used to make an initial diagnosis, a tissue biopsy of the tumor is necessary to make a definitive diagnosis to begin treatment. The tissue for diagnosis can be procured in multiple different ways which include:

• Fine needle aspiration (FNA) biopsy of the tumor: A FNA biopsy may not be helpful, because one may not be able to visualize the different morphological areas of the tumor and the tumor may be misdiagnosed. Hence, a FNA biopsy as a diagnostic tool has certain limitations, and an open surgical biopsy is preferred
• Core biopsy of the tumor
• Open biopsy of the tumor

Tissue biopsy:

• A tissue biopsy of the tumor is performed and sent to a laboratory for a pathological examination. A pathologist examines the biopsy under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis. Examination of the biopsy under a microscope by a pathologist is considered to be gold standard in arriving at a conclusive diagnosis
• Biopsy specimens are studied initially using Hematoxylin and Eosin staining. The pathologist then decides on additional studies depending on the clinical situation
• Sometimes, the pathologist may perform special studies, which may include immunohistochemical stains, molecular testing, and very rarely, electron microscopic studies to assist in the diagnosis

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Gastrointestinal Stromal Tumor of Stomach?

Gastrointestinal Stromal Tumor of Stomach may cause the following complications:

• Ulceration of the tumor can lead to secondary infections of bacteria and fungus

• Large-sized tumors may cause hemorrhaging of the gastrointestinal tract
• Compression of the underlying nerve, which can affect nerve function
• Perforation of the stomach due to presence of infiltrative tumors
• Involvement of local and distant lymph nodes

• Metastasis (spread of tumor) may involve the liver, parts of the intestine and abdominal cavity
• Complications that arise from any underlying genetic disorder, if present
• Damage to the muscles, vital nerves, and blood vessels, during surgery
• Side effects of chemotherapy (such as toxicity) and radiation
• Post-surgical infection at the wound site is a potential complication
• High risk of tumor recurrence after surgery have been reported in aggressive tumors

How is Gastrointestinal Stromal Tumor of Stomach Treated?

Treatment measures of Gastrointestinal Stromal Tumor of Stomach include:

• Wide surgical excision of GIST with removal of the entire lesion, which is followed by a course of chemotherapy, is the standard treatment method employed. The surgical excision may be performed using laparoscopic surgical techniques
• Medications: The use of tyrosine-kinase inhibitors is known to be effective in treating GIST
• Non-surgical intervention includes chemotherapy and/or radiotherapy - these modalities are generally used to shrink the tumor, if possible, before an invasive surgical procedure is planned and performed
• Arterial or chemo-embolization is used to provide temporary relief from the symptoms, and reduce blood loss during a surgical procedure
• Post-operative care is important: A minimum activity level is to be ensured, until the surgical wound heals
• Follow-up care with regular screening and check-ups are important and recommended

How can Gastrointestinal Stromal Tumor of Stomach be Prevented?

Currently, no known preventive methods exist for Gastrointestinal Stromal Tumor of Stomach. However, in case it is associated with a genetic disorder, then the following may be considered:

• Genetic counseling and testing
• If there is a family history of the condition, then genetic counseling will help assess risks, before planning for a child

Regular medical screening at periodic intervals with blood tests, scans, and physical examinations, are mandatory for those who have already endured the tumor, due to its high metastasizing potential and possibility of recurrence. Often several years of active vigilance is necessary.

What is the Prognosis of Gastrointestinal Stromal Tumor of Stomach? (Outcomes/Resolutions)

The prognosis for individuals with Gastrointestinal Stromal Tumor of Stomach depends on whether the tumor is benign or malignant. It is reported that 1 in 4 such gastric tumors may be malignant.

• The prognosis is generally excellent for benign tumors following their surgical excision and removal
• However, the prognosis of malignant GIST tumors may depend on a set of factors that include:
  • Stage of tumor: With lower-stage tumors, when the tumor is confined to site of origin, the prognosis is usually excellent with appropriate therapy. In higher-stage tumors, such as tumors with metastasis, the prognosis is poor
  • Overall health of the individual
  • Age of the individual: Older individuals generally have poorer prognosis than younger individuals
  • The size of the tumor: Individuals with small-sized tumors fare better than those with large-sized tumors
  • Individuals with bulky disease may have a poorer prognosis
  • Involvement of vital organs may complicate the condition
  • The surgical resectability of the tumor (meaning, if the tumor can be removed completely)
  • Whether the tumor is occurring for the first time, or is a recurrent tumor. Recurring tumors have worse prognosis compared to tumors that do not recur
  • Response to treatment: Tumors that respond to treatment have better prognosis compared to tumors that do not respond to treatment; good response to treatment (surgery and/or chemotherapy/radiation therapy)
  • Progression of the condition makes the outcome worse
• Generally, the prognosis of malignant GIST is variable and may be assessed on a case-by-case basis. Some are known to metastasize early and can lead to death in a few years; while others may take several years to spread to other sites. Also, some individuals are known to survive for long periods despite metastasis
• An early diagnosis and prompt treatment of the tumor generally yields better outcomes than a late diagnosis and delayed treatment

Additional and Relevant Useful Information for Gastrointestinal Stromal Tumor of Stomach:

The following article link will help you understand other cancers and benign tumors:

http://www.dovemed.com/diseases-conditions/cancer/