Treatment for gastrointestinal stromal tumors (GISTs) often depends on the extent of tumor spread. 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 (resectable) tumors
Surgery is the main treatment for 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 if the tumor is larger or did not start in the stomach, or if the cancer cells that dividing quickly (have a high mitotic rate).
If the doctor thinks that the cancer has a high risk of growing back, adjuvant treatment with imatinib (Gleevec) for up to 3 years may be recommended after surgery. This lowers the chance that the cancer will come back, and helps patients live longer.
Localized, larger (marginally resectable) 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.
If the tumor shrinks enough, 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 the tumor doesn't shrink enough to make surgery possible, imatinib is often continued as long as it seems to help. If it is no longer working or if the side effects are too severe, sunitinib may be tried instead.
Tumors that are not removable or have spread to distant sites (unresectable tumors)
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. It is continued until the tumor starts to grow (or the patient can't tolerate the side effects of the drug). If the tumor has started to grow again, it may respond to increasing the dose of imatinib. If the tumor continues to grow or the side effects from imatinib are severe, a switch to sunitinib may be helpful.
If the tumor shrinks enough with targeted therapy, surgery may then be an option in some cases. This might be followed by more targeted therapy if it is still effective.
If the cancer has spread to only 1 or 2 sites in the abdomen (such as the liver), the surgeon may advise removing the main tumor and trying to remove these other tumors as well. If this is the case, be sure to talk with your doctor about what the goals of treatment are (whether it is to try to cure the cancer, to help you live longer, or to prevent or reduce symptoms), as well as its possible benefits and risks. 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 recurrent. 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, treatment with imatinib probably offers the best chance to shrink any tumors, as long as it is still effective and the patient can tolerate taking it. If the starting dose of imatinib does not work, the dose can be increased. Another option is to try sunitinib.
If the cancer comes back as 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 helps people live longer. Some studies have found that it does, but other studies disagree. You should discuss with your doctor and family the risks and benefits of this treatment.
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