Bowel cancer – GIST


GISTs are caused by a mutation of the interstitial cells of Cajal (ICC) found in the smooth muscle of the gastrointestinal tract

ITAcC’s medical team maintains direct contact with all the specialists involved for deciding what the best treatment is for GIST patients

At iTAcC we have a highly specialized medical team in the diagnosis and treatment of gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GIST) are rare neoplasms of the digestive system that originate in the wall of the esophagus, stomach or intestine. These tumors come from a mutation in the interstitial cells of Cajal (ICC) found in the smooth muscle of gastrointestinal tract.  They are responsible for movement of contraction and peristaltic waves of the entire gastrointestinal tract. Such a mutation causes uncontrolled growth leading to the formation of a tumor. Around 5% of cases are not related to any specific DNA alteration, especially those occurring in children and associated with syndromes such as neurofibromatosis type I.

The disease commonly appears between the ages of 55 and 65, although there are exceptional cases that occur before 40.  It mainly affects males and may appear in children on sporadic occasions.

The medical team at iTAcC is highly specialized in the diagnosis and treatment of gastrointestinal stromal tumors. All treatment decisions are multidisciplinary, involving specialists in the digestive system (endoscopists), general surgeons, radiologists, pathologists, radiation oncologists, and medical oncologists. Nutritionists and physiotherapists at iTAcC provide rehabilitative support to the patient during and after treatment. All of the aforementioned provides the best guarantee in the prevention, diagnosis and treatment of disease.


Clinical symptoms of GISTs are often nonspecific.  They may appear within several disorders of the gastrointestinal tract. They are tumors of soft consistency that neither impedes the transit of intestinal contents nor the function of other organs.  This means that there are usually not symptomatic warnings in the initial stages.

The most common symptom is abdominal pain or discomfort, mild at first, but persists and worsens slowly over months or even years. Blood may appear in the stool or in vomit if the tumor ulcerates inside the intestine causing anemia and the appearance of negligible amounts of blood mixed with the stool. The first symptoms may depend on the occurrence of metastases elsewhere in the abdomen in some cases.

The most important diagnostic tests are:

  • Ultrasound (US): it is a non-invasive technique without any contraindications and is useful in the initial diagnosis of large tumors.
  • Computed tomography (CT) produces detailed cross-sectional images of the body and is able to show the tumor’s location, size as well as its possible spread to other organs or tissues.  A radiopaque contrast is injected in order to better visualize lesions in the abdomen in many cases.
  • Magnetic resonance imaging (MRI): This technique uses electromagnetic fields and waves to obtain images that allow us to differentiate lesions found in the abdomen in a very precise manner as well as determining their involvement with other organs. A contrast injection is often used as is with a CT.
  • Endoscopy with echoendoscopy: it is useful in assessing the presence and degree of local involvement of the disease.
  • Positron emission tomography (PET): With this test the degree of metabolic activity of tumor lesions can be observed.
  • Biopsy: It is necessary to take a sample of a suspicious lesion in order to perform a definitive histologic diagnosis after its discovery by imaging techniques. This is done by direct puncture of the lesion guided by ultrasound or CT. The sample is analyzed under a microscope with the aid of stains which can detect the presence of specific proteins (c-kit and CD34) in cells characteristic of gastrointestinal stromal tumors.  This is of great importance when proposing a therapeutic strategy.


ITAcC’s medical team maintains direct contact with all the specialists involved in making the best treatment decision for patients diagnosed with GIST.

At iTAcC the main objective is the administration of an individualized treatment to each patient in order to obtain the highest success rate.


The primary treatment for GIST is the surgical removal of the tumor. Its main objective is to obtain the best rate of local disease control. Small tumors can be operated on by laparoscopic techniques. The surgeon can perform a more radical intervention by partial removal of the affected organs along with the primary tumor in cases where large tumors are attached to adjacent organs.

Targeted therapies

Conventional chemotherapy is not used with GIST because it ineffective. The expression in tumor cells of a genetic alteration is the target of specific molecular therapies.  Tumor growth is inhibited by blocking pathways of tumor proliferation and dissemination.  The drugs that are used currently are:  matinib mesylate, sunitinib and nilotinib.

The presence of metastatic disease and locally advanced disease are indications for molecular therapy.  The objective is to reduce the tumor mass until reaching a size sufficient in order to perform surgery.  Molecular therapy is currently used in the most aggressive forms of the disease to accompany surgery (after) in order to prevent recurrences.


Follow up

A monitoring protocol based on a thorough control of the progress by specific imaging tests begins after treatment.

Follow up is done as in the case of all oncological activity at iTAcC, in a personalized manner with cooperation of doctors who have been involved in the diagnosis and treatment of each case. iTAcC is an open institution and works closely them.