What are Gastrointestinal Stromal Tumors?
Gastrointestinal stromal tumors or GISTs refers to a medical condition associated with formation of one of more tumors in various sections of the digestive tract including stomach, appendix, colon, esophagus, pancreas, small intestine, rectum, colon etc. If gastrointestinal stromal tumors or GISTs spreads beyond the digestive tract into the liver, it is referred as malignant gastrointestinal stromal tumors or GISTs while those that are limited to digestive tract are called noncancerous (benign) gastrointestinal stromal tumors or GISTs .
Causes of Gastrointestinal Stromal Tumors
Gastrointestinal stromal tumors are one of the forms of cancer. The exact reasons for the occurrence of gastrointestinal stromal tumors are still known as researchers are trying to find the exact causes.
What is Benign Gastrointestinal Stromal Tumors?
The particular cases of gastrointestinal stromal tumors in which the cancerous cells affect only one of more parts of the digestive tract are referred as benign gastrointestinal stromal tumors.
Symptoms of Gastrointestinal Stromal Tumors
It is hard to suspect the occurrence of gastrointestinal stromal tumors or GISTs on the basis of signs and symptoms. There are no specific symptoms to indicate the presence of tumors in digestive tract. There might not be any symptoms at all. The possible symptoms of gastrointestinal stromal tumors are as follows:
- Discomfort in bowel movement is a major symptom of gastrointestinal stromal tumors or GISTs.
- Presence of traces of blood in stool an vomit.
- Feel like vomiting.
- Pain or discomfort in the abdomen.
- Development of unusual extra tissue in the abdomen.
- Feeling tired due to lack of RBCs in blood.
The symptoms of gastrointestinal stromal tumors or GISTs are not particular and are similar to those that can occur in other medical conditions.
Tests to Diagnose Gastrointestinal Stromal Tumors
The following tests are used to diagnose the occurrence of gastrointestinal stromal tumors or GISTs:
- Computed tomography (CT or CAT) scan for diagnosing gastrointestinal stromal tumors is one of the most effective techniques to get a 3-dimensional computerized image of the presence of tumor or abnormality in the digestive tract. The image can also give an idea of the size of location of the tumor without needing to make any cut or insert anything in the body. The image is created using the X-rays to which the body is exposed.
- Fecal occult blood test is a laboratory method of detecting any traces of blood that cannot be seen with naked eye in a sample of stool.
- Barium swallow and x-ray is an X-ray analysis of the complete digestive tract after the patient has been made to swallow barium. The barium settles along the lining of the GI and helps in getting a clear image of any abnormality or tumor in the digestive tract.
- Endoscopy for diagnosing gastrointestinal stromal tumors or GISTs involves insertion of a special probe called gastroscope into the digestive tract to look for any abnormalities. The probe is basically a tube equipped with light and is used to give an image on the computer screen. There are two types of endoscopy: upper endoscopy and lower endoscopy. If the tube is inserted through the mouth, it is termed as upper endoscopy whereas the tube is inserted through anus in lower endoscopy. Both the options are uncomfortable for the patient and thus he is given light sedatives.
- Endoscopic ultrasound is another non-invasive technique to detect the presence of any tumors in stomach. It involves use of sound waves whose reflection is recorder to create the image.
- Magnetic resonance imaging (MRI) is advanced scanning method where magnetic fields are used to create an image of the tumor in digestive tract. A dye usually referred as contrast medium is injected into the veins to produce a clearer picture.
- Positron emission tomography (PET) scan. The cells of the cancer consume more energy as compared to the other cells. In this method the patient is required to consume a radioactive sugar substance whose amount of absorption that can be measured.
- Biopsy is another lab test for gastrointestinal stromal tumors or GISTs in which a small part of tissue of the patient is used to study any abnormalities in the sample.
How are Gastrointestinal Stromal Tumors Treated?
There is a multidisciplinary team of specialists doctors that decision on treatment procedures and operations for gastrointestinal stromal tumors or GISTs patients. The important aspects that determines the choice of treatment are preferences of the patient, the severity or stage of cancer, potential side effects of the treatment and the present state of health of the patient.
The various treatment options available for the treatment of gastrointestinal stromal tumors or GISTs are as follows:
Surgery for Gastrointestinal Stromal Tumors
The best treatment option for getting rid of the tumor in case of gastrointestinal stromal tumors or GISTs patients is surgery. This treatment option is particularly more effective in case of a localized gastrointestinal stromal tumors or GISTs. In localized gastrointestinal stromal tumors, the tumors are present in only a specific part of the digestive tract and thus it is easier to remove the tumors completely. The surgery is performed by a specialist known as surgical oncologist.
In case of the large tumors, the doctors try to initially reduce the size of the tumor by an approach called as imatinib. Once the size of the tumor is reduced to a manageable size, the surgery can be performed to safely remove the tumor completely from the specific location without harming the surrounding organs.
Although the tumor is completely removed, there is always a risk of re occurrence of the tumor. Thus, surgery is followed by post surgical treatment termed as adjuvant therapy for at least 3 years during which the patient receives imatinib.
Targeted Therapy for Gastrointestinal Stromal Tumors
Tyrosine kinase inhibitors (TKIs) for Gastrointestinal Stromal Tumors: There is special type of proteins termed as kinases in our cells that promote the survival and growth of tumor. This approach make use of special drugs tyrosine kinase inhibitors that targets this protein and thus helps in preventing the spread of gastrointestinal stromal tumors or GISTs. This ensures that the tumor does not grows and harms the surrounding organs or block the digestive tract.
Imatinib (Gleevec) for Gastrointestinal Stromal Tumors or GISTs: Imatinib is the most effect effective drug that can be used to restrict or even shrink the size of the tumor or tumors in various parts of the digestive tract. It cannot be used exclusively as the treatment option for gastrointestinal stromal tumors or GISTs but works well in combination with the surgery. It is used both before and after the surgery. It is the only drug that is approved by FDA i.e. the Food and Drug Administration authority in US.
The drug helps in reducing the size of the tumors before the surgery and prevents re occurrence of the tumor after the surgery. It is particular useful in case of GIST where tumors are present in multiple locations. The standard dosage starts from 400 mg daily that can be increased to 800 mg as per the requirement.
Radiation Therapy for Gastrointestinal Stromal Tumors
Radiation therapy is another option that can be used as a support therapy to offer some relief to the patients suffering from gastrointestinal stromal tumors. It does not work as a treatment option but as palliative treatment that helps in easing off the pain and prevent bleeding. In this process, the portion of the digestive tract that is affected by cancer cells is exposed to strong X-rays. These high energy rays have the capacity to destroy cancer cells to some extent and thus preventing the tumor from getting severe. There can be two types of radiation therapies: internal radiation therapy and external radiation therapy. External-beam radiation therapy is more common in which the radiations are provided using an external X-ray machine. In case of internal radiation therapy, implants are used.
Radiation therapy is a repetitive therapy that needs to be continued over a long period with many sessions of the therapy on regular intervals. Radiation therapy is not very popular as it does not offer complete treatment also offers some side effects. There is always a risk that high energy radiations may also destroy or harm healthy cells in the process. Some other side effects of the radiation therapy are loose bowel movements, mild skin reactions, tiredness, upset stomach etc…
Chemotherapy for Gastrointestinal Stromal Tumors
Chemotherapy is a popular treatment option for various types of cancers but does not work well in case of gastrointestinal stromal tumors or GISTs. Chemotherapy involves uses of particular drugs that gradually destroys the cancer cells and prevent them from growing.
Risk Factors for Gastrointestinal Stromal Tumors
The exact causes of gastrointestinal stromal tumors are still unknown but there are some factors that can increase the risk of developing gastrointestinal stromal tumors:
- Gender. The risk of gastrointestinal stromal tumors is higher in case of men as compared to women.
- Age. Older people with an age of more than 50 years are at higher risk of gastrointestinal stromal tumors or GISTs .
- Heredity. If someone in your family is suffering from gastrointestinal stromal tumors or GISTs, the risk of occurrence of gastrointestinal stromal tumors or GISTs at some point in time increases in case of other members of the family.
- Genetics. Gastrointestinal stromal tumors or GISTs occurs as result of genetic mutations and thus any sort of mutation in the body increases the risk of tumors.