What You Need to Know About GIST
How is GIST Treated?
GIST has become a treatable cancer. Surgery is the primary treatment of GIST if the disease has not spread and is resectable. In fact, in many cases once the original tumor is surgically removed, you may not need further treatment at all.
“Many people are cured by some fairly simple surgery,” says George Demetri, MD, associate professor of medicine at Harvard Medical School and director of the Center for Sarcoma and Bone Oncology at the Dana-Farber Cancer Institute and Brigham and Women's Hospital in Boston. “Well over half of all cases of GIST are small, low-grade tumors and easily removed surgically.”
Once the tumor is removed surgically, the tumor will be examined under a microscope to try to confirm the diagnosis and to test the tumor for certain mutations.
There are certain factors that make GIST more likely to recur:
Tumor size. The larger the tumor, the more likely it is to recur after surgery. Small-sized GISTs may recur as well. Therefore, size is only one variable for recurrence.
The “mitotic index.” This means the proportion of cells that are making copies of themselves. The higher the mitotic index, the higher the risk of recurrence.
Tumor location. GIST that is found in the stomach is less likely to recur as compared to GIST found in other sites of origin.
Based on these factors, the risk of recurrence of GIST is classified as low, intermediate, or high.
“For probably seven out of 10 patients whose tumors can be surgically removed, the pathology report will tell us that they don’t have a big risk of the cancer ever coming back -- maybe 10% in their entire lifetime,” says Demetri.
Regardless of recurrence risk, everyone with a diagnosis of GIST should be evaluated at 3- to 6-month intervals.
CT scans of the abdomen and pelvis should also be performed every 3 to 6 months. PET scans are not a replacement for CT scans.
Prior to this year, imatinib (Gleevec) was used as an adjuvant therapy for high-risk, resected GIST. The therapy was given for one year. Overall survival was improved with this therapy.