We hear about stomach cancer and colon cancer a lot. But there’s another type of cancer that can affect the gastrointestinal (GI) tract that’s not so familiar. It’s called GIST, which stands for gastrointestinal stromal tumors.
“GIST tumors arise in adults usually between 40 and 70 years old and are not seen in children.” said Mark Gimbel, MD, a surgical oncologist at Banner MD Anderson Cancer Center at Banner Gateway Medical Center in Arizona. They sometimes run in families but more often develop spontaneously.
These tumors can grow anywhere in the GI tract, including the esophagus, stomach, duodenum, small intestine, colon and rectum. They spring from the muscle layers of the intestines, which makes them different from colon or stomach cancers. Those cancers come from the glandular cells in the lining of the GI tract and behave differently than GIST.
Here’s how they differ:
- Stomach and colon cancers show up on an endoscopy, whereas GISTs appear as a smooth bulge in the wall of the GI tract.
- Stomach and colon cancers are more likely to spread to the lymph nodes, compared to GISTs.
- Since GISTs come from different types of cells than stomach and colon cancers, treatments are not the same.
In fact, these tumors aren’t even classified as cancerous or noncancerous. Instead, they are treated based on how likely they are to recur.
Smaller tumors that are found in the stomach and are growing slowly have a low risk of recurring. Larger tumors that are found in the small intestine and are growing quickly have a high risk of recurring.
You may not notice symptoms
Smaller GISTs don’t typically cause symptoms. However, as they get larger, they may cause these symptoms, depending on where in the GI tract they develop:
- Abdominal pain or mass
- Loss of appetite
- Weight loss
- Bleeding into the abdomen
- Bleeding into the intestinal tract, which could show up in the stool
What happens if your doctor suspects GIST?
“GISTs are typically diagnosed with an endoscopy or a CT scan based on how they look, but the only way to make an accurate diagnosis is by either taking a piece of the tumor or cutting the tumor out for the pathologist to evaluate,” Dr. Gimbel said.
If you’re diagnosed with GIST, your doctor will recommend a treatment plan based on its size and location. Some tumors can be easily removed with surgery and removing them can cure GIST.
Surgeons can often remove small tumors with minimally invasive techniques such as laparoscopy or robotic techniques. And about 70 percent of patients have small tumors, and they are cured after the tumors are removed.
If examining the tumor shows it has a high risk of recurring, your doctor will probably recommend a three-year course of imatinib (Gleevec) after surgery to decrease the risk of it coming back. Imatinib is an oral medication that is well tolerated. It’s a targeted therapy that goes after a mutation in a gene that is responsible for more than 90 percent of these tumors.
Larger tumors may involve other organs and be difficult to remove. Treating them with imatinib before surgery can shrink the tumors and make it safer and easier to remove them.
The bottom line
Gastrointestinal stromal tumors are rare tumors that develop in the digestive tract. Even though they might appear in the same places as stomach or colon cancers, they stem from different cells and are treated differently. There are good treatment options for curing these GISTs.
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