Although GISTs are not formally staged, the treatment options often depend on the extent of the tumor. The main treatment is surgery to remove the tumor when possible, but targeted therapies and other treatments may also help in some situations.

Localized, smaller tumors

Surgery removes smaller tumors. In some patients, this is the only treatment needed. Still, even when they are removed completely, about half of GISTs come back within 2 years. The chance that a GIST will come back is higher in larger tumors and in those with cancer cells that are dividing rapidly (have a high mitotic rate) If the doctor thinks that the cancer has a high risk of growing back, treatment with imatinib may be started after surgery.. Treating with anti-cancer drugs after the cancer has been removed completely with surgery is known as adjuvant therapy. Taking imatinib can lower the chance that a GIST will come back (at least for a time), but it is not clear if it really prevents the cancer from coming back or if it just postpones it. So far, it is still too early to tell if this treatment helps patients live longer. The use of adjuvant treatment for GISTs is still being studied.

Localized, larger tumors

Larger tumors may be harder to remove completely and might require more extensive surgery, which could cause health problems later on. Because of this, once a biopsy is done to confirm the tumor is a GIST, treatment with imatinib is usually started. It is continued at least until the tumor stops shrinking. Then, surgery may be done if the surgeon feels that the remaining tumor can be removed safely. Imatinib may be continued after surgery to lower the chance that the cancer will come back. If surgery still isn't possible, this drug is often continued as long as it seems to help.

Tumors that are not removable or have spread to distant sites

Treatment options for GISTs that are not resectable or have metastasized may depend on where they have spread and how extensive the spread is.

For most of these tumors, imatinib is the preferred first option, as it may shrink them. It is continued until it is no longer effective (the tumor starts to grow). Some tumors respond to increasing the dose of imatinib. If the tumor shrinks enough, surgery may then be an option. If the tumor continues to grow or the side effects from imatinib are severe, a switch to sunitinib may be helpful.

If the cancer has spread to only 1 or 2 sites in the abdomen (such as the liver), the surgeon may remove the main tumor and try to remove these other tumors as well. If this is the case, you should discuss the risks and benefits of this approach to treatment with your doctor and family. Usually this should be considered only for tumors that are slow growing or those causing local complications such as uncontrollable bleeding.

There are also newer ways to treat cancers that have spread to the liver. These treatments may include cryosurgery (freezing the tumor), radiofrequency ablation (RFA; using electric currents to heat the tumor), embolization (injecting material into large blood vessels feeding the tumor to block blood flow), or ethanol ablation (injecting concentrated alcohol into the tumor). These methods do not require surgery. The freezing probe, RFA probe, or needle is inserted through the skin and guided to the tumor by CT (computed tomography) scans or ultrasound images. The value of these treatments in patients with a GIST is not fully known because not enough studies have focused on this rare type of cancer.

Recurrent tumors

When a cancer comes back after treatment, it is called recurrence. If the cancer comes back (recurs) in or near the place it started, it is called a local recurrence. If it recurs at other sites (like the lungs or liver) it is called a distant recurrence. Treatment options for GISTs that recur after treatment depend on the location and extent of the recurrence.

For most recurrences, doctors will likely recommend treatment with imatinib, as it probably offers the best chance to shrink any tumors. If the first dose of imatinib does not work, the dose can be increased. Another option is to try sunitinib.

For the recurrence of a single, well defined tumor, removing or destroying the tumor may be an option. Doctors are still not certain if removing GISTs that come back after treatment really helps people live longer. Some studies found that it did, but other studies disagreed. You should discuss with your doctor and family the risks and benefits of this treatment.

Last Medical Review: 05/11/2009
Last Revised: 05/11/2009