WHAT IS GIST?
GIST, once regarded as a single disease, is now divided into several different forms, based on the presence of specific mutations (genetic changes) in the cancer cells. Most types affect adults, but some affect children, and a few are familial (running in families). Mutations in several genes have been identified as “drivers” of GIST cancers, including the KIT, PDGFRA, SDH, and NF1 genes. Understanding GIST can be challenging.
In some cases, no driver mutation has been identified. These are classified as “wildtype” GIST. As science advances, we expect that mutations driving these wildtype GISTs will be identified. However, regardless of the type of GIST that a patient has, learning as much as possible about the disease is important. As we say, “the wonder drug of the 21st Century is the informed patient”.
What type of cancer is GIST?
GISTs belong to a group of cancers called soft tissue sarcomas. Sarcomas are less-common cancers that develop in connective or supporting tissues. Sarcomas are derived from the general class of cells known as “mesenchymal cells”, found in bone, muscle, fat, cartilage, etc. In contrast, most, more common cancers, such as lung, skin, and prostate cancer, develop from epithelial cells which are found on the linings of the body’s many surfaces; such cancers are called carcinomas.
Carcinomas and sarcomas behave very differently and are also treated very differently. Since sarcomas are far less common than carcinomas, there are fewer oncologists who specialize in their treatment.
Where do GISTs usually occur?
GISTs may arise anywhere in the digestive tract. The most common sites are the stomach (40-70%), the small intestine (20-40%), and the colon and rectum (5-15%). GISTs can also be found in the esophagus (<5%). (Although very rare, GISTs can develop outside the intestinal tract in the abdominal cavity, these are called eGISTs.)
At the time of diagnosis, most GISTs (80-85%) are limited to a single site (“localized”). However, as the disease progresses, GIST may spread from the original (primary) site to distant locations. If this happens, these secondary tumors are called metastases (or simply, “mets”). It is less common (15-20%) for patients to be metastatic at diagnosis. If GIST tumors do metastasize, they usually travel to the liver, or the peritoneum. Metastases to the lymph-nodes and lungs are rare but do also occur.
Diagnosis of GIST can be difficult – GIST tumors can grow quite large before they are found, and primary tumors often produce few symptoms. GISTs are often spotted during emergency surgery brought about by unexpected perforation of the gastrointestinal tract and consequent bleeding. When GIST tumors are first discovered,
Most common symptoms are:
- Vague abdominal discomfort or pain.
- Presence of a palpable abdominal mass.
- Feeling of abdominal fullness.
- Secondary symptoms resulting from tumor bleeding and associated anemia.
More information: https://liferaftgroup.org/