All about Gastrointestinal stromal tumors - Causes, Symptoms, and Treatment

Gastrointestinal stromal tumours (GISTs) could be found in any part of the digestive system but mostly in the stomach and the small intestine. Commonly known as the soft tissue sarcomas, GISTs are mutated cells of the nervous system present across the digestive system to regulate the digestive movements.

Like any other tumor, there are two types in GISTs - Benign and cancerous. Skim through the blog as we dive deep into GISTs, exploring the causes, symptoms, diagnosis, treatment options, and much more. 

What causes GISTs?

There is no valid reason behind the occurrence of GISTs. However, it is attributed to the KIT protein. The KIT protein is found in the cell membrane and is responsible for the process called phosphorylation, which leads to the activation of a series of proteins that present in multiple signaling pathways. 

The tumors occur when there is a mutation in the expression of the KIT protein. GISTs grow outwards spreading across the nearby cells, and to organs. 

Who is at the risk zone of GISTs?

GISTs can occur randomly but people who have GISTs run in their families and people who are born with the mutations in SDHB and SDHC genes are at greater risk and so the people who are above 60. 

Symptoms of GISTs

The symptoms of GISTs can occur over a period of time. It all can start with a pain or discomfort in the abdomen followed by bloody stools, nausea, vomiting, bowel obstruction, tiredness, feeling full stomach, and fatigue. 

It does not mean you have GISTs if you are experiencing any of these symptoms. These are the common symptoms of many digestion problems, abdominal bloating, hernia problem, GERD issues, and hemorrhoids. 

If you observe any of these symptoms, it is highly recommended to consult your gastric doctor to determine the root cause and take appropriate treatment. 

Diagnosis process

Followed by a thorough physical examination and evaluation of symptoms and medical history, the gastro specialist will conduct tests and imagery examinations to determine the presence of GISTs. The following tests may take place in the diagnostic process of GISTs. 

Upper endoscopy - After giving a mild sedative, a smooth, flexible tube with a small light bulb as the head (endoscope) is slid through the mouth. The tube is passed down through the esophagus, stomach, and intestines to check for the tumours. It is also used to collect the sample of abdominal tissue for further examination. 

CT Scan - The contrast-enhanced computerized tomography takes multiple x-ray images of the abdomen and various digestive organs to produce detailed cross-sectional images that show the presence of tumours (if any). 

Apart from these two diagnostic methods, endoscopic ultrasound (EUS), fine-needle aspiration biopsy, and laboratory tests are conducted using the collected samples. This helps the gastric specialist to find a better approach to treatment. 

Treatment for GISTs

Some tumours might not grow and some might show quick growth spreading to the other structures or organs. Treatment for GISTs is provided purely based on the type of tumour, the size, location, and the quickness of growth. The treatment options typically include surgeries and targeted drug therapy. 

If the tumour is small: 

Smaller tumours that are not showing faster growth are considered as resectable (removable) tumours. The recurring chances will be low in these tumours and periodic endoscopy is required followed by the surgery. 

If the tumour is large: 

If the tumour is large and not resectable, targeted drug imatinib (Gleevec) is performed to shrink it. Then the specialist will explore the option of removing it after validating the potential risks involved in doing so.   

The treatment for GISTs is relatively a simple process in the first scenario where the tumours are small and resectable. For the larger and recurrent tumours, targeted drug therapy is one option. Radiation therapy is considered in cases where there are excessive pain and discomfort. 

What you could do to avoid GISTs?

Inherited genetic syndromes that might lead to GISTs are the ones to look out for. Consider a medical check if these syndromes run in your family. 

 Making certain lifestyle changes such as eating right, maintaining a healthy weight, quitting smoking, and periodic medical checkups at your nearest gastro clinic will help.