GIST is an acronym that stands for gastrointestinal stromal tumor.
This type of cancer starts in interstitial cells of Cajal (ICCs), which are special cells that line the walls of the gastrointestinal (GI) tract.
ICCs send signals to the GI muscles. These signals cause them to contract, which allows them to move food and liquid through the digestive system.
GISTs can form anywhere in the GI tract, but they’re most likely to grow in the stomach or small intestine. These tumors are usually small but can be larger.
Some are more likely than others to spread to other parts of the body.
Surgery is the main treatment for GISTs that haven’t spread. However, surgery may not be an option for tumors that have spread.
Surgical resection is the medical term for the surgical removal of tissue. In the case of GIST, the goal of the procedure is to remove as much of the tumor as possible.
A healthcare professional might recommend surgery if your tumor is at least 2 centimeters (cm) in size or if you’re experiencing symptoms.
If your tumor is smaller than 2 cm and not causing symptoms, your doctor may wait and watch to see if it grows or otherwise changes.
Surgery is also typically recommended only if the cancer has not metastasized, or spread to other areas of the body. And doctors may advise against surgery if a tumor is located in an area where the procedure would significantly damage surrounding organs.
A healthcare professional may prescribe a targeted therapy after surgery if there are cancer cells remaining or there’s a chance the tumor could recur.
A less invasive surgery known as laparoscopy is usually used for small GISTs that measure more than 2 cm but less than 5 cm.
During laparoscopy, a surgeon makes a few small cuts in the skin. A thin tube with a light and camera on the end goes into one of the openings. This lets the surgeon see inside your body to perform the procedure.
Surgical instruments go into the other holes. The surgeon uses them to remove the tumor and some of the tissue around it.
Open (or extensive) surgery may be an option for tumors larger than 5 cm that can be safely removed. A surgeon will make a single cut in the skin and take out the tumor as well as some of the tissue around it.
Your doctor may give you a targeted therapy to shrink the tumor before surgery.
In some cases, the surgeon might need to remove part of an organ to make sure all the cancer is gone.
Some of the organs that GIST can affect are your:
- stomach (partial gastrectomy)
- intestine (partial intestine resection)
- rectum and anus (abdominoperineal resection)
- pancreas and intestine, plus possibly part of the stomach and gallbladder (Whipple procedure)
Metastatic GISTs are ones that have spread to other parts of your body. Most often, the cancer spreads to the liver or the peritoneum (the lining of your abdominal cavity).
If you have a metastatic GIST or your cancer comes back (recurs) after surgery, your doctor will recommend targeted therapy. These medications shrink tumors.
Surgery may not be an option if the cancer has already spread to many different places. But if you have only one or two tumors, it may still be possible to surgically remove them.
Some tumors are unresectable, which means they can’t be surgically removed.
This may be because they are too large to remove safely or located in a place where removing them could damage a nearby organ.
Other tumors aren’t appropriate for surgery because they’re metastatic, or have spread to other parts of the body.
There are other ways to treat these tumors.
Targeted therapy drugs, known as tyrosine kinase inhibitors (TKIs), identify and kill cancer cells with certain genetic changes. This treatment usually causes less damage to healthy tissues than chemotherapy or radiation.
Your doctor will run a genetic test on your tumor to confirm it’s a GIST and determine its precise genetic mutations. GIST tumors usually have mutations in the KIT or PDGFRA genes.
TKIs usually control tumors well initially but often stop working over time. Doctors will usually prescribe these drugs in the following order, changing the medication when a person’s current treatment no longer works:
- imatinib (Gleevec)
- sunitinib (Sutent)
- regorafenib (Stivarga)
- ripretinib (Qinlock)
If your tumor tests positive for a rare genetic mutation known as PDGFRA exon 18, it won’t respond well to standard treatments. Your doctor may prescribe avapritnib (Ayvakit), which is approved specifically for this mutation.
Sometimes surgery becomes an option if you have a large tumor that shrinks enough with these medications.
Other medications may work for people who don’t respond to the targeted drugs above. The following drugs are currently being studied for GISTS:
- binimetinib (Mektovi)
- dasatinib (Sprycel)
- nilotinib (Tasigna)
- pazopanib (Votrient)
- ponatinib (Iclusig)
- sorafenib (Nexavar)
When a GIST continues to grow while you’re on targeted therapy, other treatment options include:
- removal of the tumor using heat (radiofrequency ablation)
- radiation therapy to relieve pain and other symptoms
- surgery to remove as much of a tumor as possible (resection)
If your tumor continues to grow even with treatment, consider enrolling in a clinical trial. These studies test new targeted therapies and other drugs that work against certain gene mutations.
Some studies are looking at immunotherapy. This is treatment that boosts your own immune system to help it fight cancer.
Taking part in a clinical trial could give you access to a treatment that works better against your cancer than treatments you’ve already tried.
Expect to stay in the hospital for 7 to 10 days after GIST surgery. Recovery from laparoscopic surgery is faster than with open surgery.
It should take between 3 and 6 weeks for you to recover from surgery, but it can take up to 1 year to fully heal. Your surgeon can give you a better idea of your expected recovery time.
Most people with smaller GISTs are able to get back to their usual life after surgery.
Surgery can cure GIST that hasn’t spread.
Taking a targeted therapy after surgery can reduce the chance that the cancer will come back.
Survival rates after surgery depend on where the tumor is and where it has spread.
When tumors are small enough to remove with surgery, outlook is very good. A small 2018 study reported a 5-year survival rate of 92 percent.
Surgery is the main treatment for GISTs. For small tumors, surgery is done laparoscopically through small incisions. Larger tumors require open surgery.
Sometimes the surgeon has to remove part of the stomach or another organ close to the tumor. Your doctor will let you know what to expect after your surgery.
If your cancer isn’t treatable with surgery, you have other options.
Targeted drugs, procedures to burn off the tumor, or a clinical trial might help shrink your cancer. These treatments could help you live longer with a better quality of life.