A gastrointestinal stromal tumoura tissue mass that forms from groups of unhealthy cells (GIST) is a rare type of sarcomacancer arising from bones and/or soft tissue that forms in lining of the gastrointestinal tract. More specifically, they develop in interstitial cellsthe basic structural and functional unit of all living things of Cajal (ICC), which play a critical role in the intestinal contractions required for digestion. The gastrointestinal tract is primarily responsible for food digestion and nutrient uptake, and is made up of organs such as the stomach, small intestinea section of the gastrointestinal tract that recieves food from the stomach and absorbs the nutrients from food, also called small bowel, and large intestine.
GISTs in adults are slightly more common in males and are generally diagnosed in people between the ages of 50 and 70. They are most commonly found in either the stomach, or the small intestine. While this disease has higher incidence in adults, children and teenagers are also able to develop this disease. In paediatric cases, GISTs are more common in girls and tends to be diagnosed in the teen years. In children and teenagers, GISTs are usually found in the stomach.
Treatment
If a GIST is detected, it will be staged and graded based on size, metastasiswhen the cancer has spread to other parts of the body, also known as mets, and how the cancera disease where abnormal cells split without control and spread to other nearby body tissue and/or organs cells look under the microscope. Stagingthe process of determining how big the cancer is, where it started and if it has spread to other areas and grading helps your doctors determine the best treatment for you.
Cancers can be staged using the TNM staging system:
- T (tumour) indicates the size and depth of the tumour.
- N (nodea small lump or mass of tissue in your body) indicates whether the cancer has spread to nearby lymph nodessmall bean-shaped structures that filters harmful substances from lymph fluid.
- M (metastasis) indicates whether the cancer has spread to other parts of the body.
This system can also be used in combination with a numerical value, from stage 0-IV:
- Stage 0: this stage describes cancer cells in the place of origin (or ‘in situ’) that have not spread to nearby tissuea group of cells that work together to perform a function.
- Stage I: cancer cells have begun to spread to nearby tissue. It is not deeply embedded into nearby tissue and had not spread to lymph nodes. This stage is also known as early-stage cancer.
- Stage II: cancer cells have grown deeper into nearby tissue. Lymph nodes may or may not be affected. This is also known as localisedaffecting only one area of body cancer.
- Stage III: the cancer has become larger and has grown deeper into nearby tissue. Lymph nodes are generally affected at this stage. This is also known as localised cancer.
- Stage IV: the cancer has spread to other tissues and organs in the body. This is also known as advancedat a late stage, far along or metastatic cancer.
Cancers can also be graded based on the rate of growth and how likely they are to spread:
- Gradea description of how abnormal cancer cells and tissue look under a microscope when compared to healthy cells I: cancer cells present as slightly abnormal and are usually slow growing. This is also known as a low-grade tumour.
- Grade II: cancer cells present as abnormal and grow faster than grade-I tumours. This is also known as an intermediate-grade tumour.
- Grade III: cancer cells present as very abnormal and grow quickly. This is also known as a high-grade tumour.
Once your tumour has been staged and graded, your doctor may recommend genetic testinga procedure that analyses DNA to identify changes in genes, chromosomes and proteins, which can be used to analyse tumour DNA to help determine which treatment has the greatest chance of success, which analyses your tumour DNA and can help determine which treatment has the greatest chance of success. They will then discuss the most appropriate treatment option for you.
Treatment is dependent on several factors, including age, location, stage of disease and overall health.
Treatment of Childhood GIST
Due to the rarity of GIST in childhood, there are fewer treatment options than adults with GIST. Treatment options for childhood GIST may include:
- Surgerytreatment involving removal of cancerous tissue and/or tumours and a margin of healthy tissue around it to reduce recurrence, potentially including:
- Gastrectomycomplete or partial removal of the stomach.
- Complete or partial resectionsurgical removal of tissue or part/all of an organ of the intestine.
- Abdominoperineal resectionsurgical removal of the anus, rectum and a portion of the sigmoid colon through an incision in the abdomen.
- Pancreaticoduodenectomyremoval of part of the pancreas (generally the head), the first part of the small intestine (duodenum), part of the stomach, the gallbladder, and part of the common bile duct; also known as a Whipple procedure, also known as a Whipple procedureremoval of part of the pancreas (generally the head), the first part of the small intestine (duodenum), part of the stomach, the gallbladder, and part of the common bile duct; also known as a pancreaticoduodenectomy.
- Targeted therapymedication that targets specific molecular features of cancer cells.
- Clinical trialsresearch studies performed to test new treatments, tests or procedures and evaluate their effectiveness on various diseases.
- Palliative carea variety of practices and exercises used to provide pain relief and improve quality of life without curing the disease.
Treatment of GIST in adults
Adults with GIST have more treatment options that children with this disease. However, like childhood GIST, chemotherapya cancer treatment that uses drugs to kill or slow the growth of cancer cells, while minimising damage to healthy cells and radiation therapya treatment that uses controlled doses of radiation to damage or kill cancer cells are not often used to treat this type of cancer.
Treatment options for GISTs in adults may include:
- Surgery, potentially including:
- Gastrectomy.
- Complete or partial resection of the intestine.
- Abdominoperineal resection.
- Pancreaticoduodenectomy, also known as a Whipple procedure.
- Targeted therapy.
- Watch and waitthe close monitoring of a cancer without giving treatment until symptoms appear or worsen.
- Clinical trials.
- Palliative care.
Some of the information regarding treatment was obtained from the Gastrointestinal Stromal Tumors Treatment (Adult) (PDQ) and the Childhood Gastrointestinal Stromal Tumours Treatment (PDQ) pages published by the National Cancer Institute.
Risk factors
The riskthe possibility that something bad will happen factors for developing GIST, as an adult or a child, include having genetic conditions such as:
- Neurofibromatosis type 1 (NF1).
- Carney triad.
- Carney-Stratakis dyad.
- Familial GIST syndrome.
Certain genetic mutations have also been linked to the development of GIST. The genes commonly affected include:
- Tyrosine c-KIT.
- PDGFRA (platelet derived growth factor receptor alpha) receptors.
Some fewer common genes affected can include:
- Succinate Dehydrogenase (SDH).
- Neurofibromatosis gene 1 (NF1).
- BRAF V600
- Rat sarcoma (RAS).
Not everyone with these risk factors will develop the disease, and some people who have the disease may have none of these risk factors. See your general practitioner (GP) if you are concerned.
Symptoms
GIST may appear asymptomatic in the early stages. Adults and children with GIST may experience some of the following symptoms:
- Bloodthe red bodily fluid that transports oxygen and other nutrients around the body in stoolwaste product from the bowel sent to the anus for removal; also known as faeces or poo and/or vomit.
- Abdominal pain and/or massa growth of cells that come together to make a lump, may or may not be cancer.
- Bloating.
- Fatiguea state of extreme tiredness or exhaustion, can be physical or mental.
- Difficulties/pain when swallowing.
- Unexplainable weight loss/loss of appetite.
- Nauseato feel sick or likely to vomit and/or vomiting.
- Anaemiaa condition where there aren't enough red blood cells in the blood, causing fatigue, weakness and pale skin and affecting how the body responds to infection.
- Blocked intestinesportion of the digestive system that digests food (small intestine) and absorbs salts and water (large intestine), also called bowel, which carry its own set of symptoms:
- Abdominal cramping and/or swelling
- Nausea and/or vomiting.
- Diarrhoeafrequent discharge of watery or loose stools from the body.
- Constipationa condition where a person has difficulty passing faeces/stools.
Not everyone with the symptoms above will have cancer, but see your GP if you are concerned.
Diagnosis
If your doctor suspects you have a GIST, they may order the following tests to confirm the diagnosisthe process of identifying a disease based on signs and symptoms, patient history and medical test results and refer you to a specialist for treatment:
- Physical examinationan examination of your current symptoms, affected area(s) and overall medical history.
- Imagingtests that create detailed images of areas inside the body tests, potentially including:
- MRI (magnetic resonance imaging)a type of medical imaging that uses radiowaves, a strong magnet and computer technology to create detailed images of the body.
- CT (computed tomography) scana type of medical imaging that uses x-rays and computer technology to create detailed images of the body.
- PET (positron emission tomography) scana type of medical imaging that uses radioactive tracers to create detailed images of the body.
- Endoscopic ultrasoundan ultrasound taken during an endoscopy.
- Blood teststesting done to measure the levels of certain substances in the blood.
- Endoscopya procedure that involves inserting a long, flexible tube with a light and small camera (endoscope) into the body to view internal organs, most commonly a gastroscopyexamination of the stomach and part of the small bowel with a small, flexible instrument known as a gastroscope.
- Biopsyremoval of a section of tissue to analyse for cancer cells.
