Treatment Choices for Gastrointestinal Stromal Tumor Based on Tumor Spread
Treatment for gastrointestinal stromal tumors (GISTs) depends on the size of the tumor, where it is, how far it has spread, and how quickly it is growing. 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 most small tumors. For tumors that are small and are not growing quickly, this is often the only treatment needed.
The chance that a GIST will come back after surgery is higher if the tumor is larger or did not start in the stomach, or if the cancer cells are dividing quickly (have a high mitotic rate). If the doctor thinks that the cancer has an intermediate or high risk of growing back based on these factors, adjuvant treatment with the targeted drug imatinib (Gleevec) is typically recommended for at least a year after surgery. For tumors that are highly likely to come back, many doctors now recommend giving patients at least 3 years of imatinib.
For some very small tumors (less than 2 cm across) that are found incidentally and are not causing any symptoms, another option may be just to watch the tumor carefully with endoscopy once or twice a year. If it is not growing, you might not need further treatment.
Localized, larger (marginally resectable) tumors
Tumors that are larger or in certain places may be harder to remove completely and might require more extensive surgery that 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 might be done if the doctor thinks he or she can remove the remaining tumor safely. The patient might continue to take imatinib 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 (Sutent) may be tried instead. If sunitinib is no longer working, the targeted drug regorafenib (Stivarga) may help some patients.
Tumors that are not removable or have spread to distant sites (unresectable tumors)
Treatment options for GISTs that cannot be removed with surgery (are unresectable) or have spread (metastasized) depends on where they have spread and how extensive the spread is.
For most of these tumors, imatinib is the preferred first treatment option. It is continued as long as the tumor doesn’t grow (and the patient can tolerate the side effects of the drug). If the tumor starts 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 too severe, a switch to sunitinib may be helpful. If sunitinib is no longer working, regorafenib may help some patients.
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.
Other options to treat cancers that have spread to the liver include ablation and embolization. These treatments may include radiofrequency ablation (RFA; using electric currents to heat the tumor), or ethanol ablation (injecting concentrated alcohol into the tumor).
For ablation, a probe or needle is inserted through the skin and guided to the tumor by CT (computed tomography) scans or ultrasound images, then the tumor is destroyed by heat, cold, or an injection of alcohol.
For embolization material is injected into large blood vessels feeding the tumor to block blood flow and kill cancer cells. These treatments can shrink the tumors in the liver, but are not expected to cure the cancer.
Cancers that are no longer responding to the targeted drugs discussed above can be hard to treat. Some doctors may recommend trying other targeted drugs, such as sorafenib (Nexavar®), dasatinib (Sprycel®), or nilotinib (Tasigna®), although it’s not yet clear how helpful these drugs are. Standard chemotherapy drugs are usually not very effective. Taking part in a clinical trial of a newer treatment may be a good option for some people.
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 is probably the best way 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 or regorafenib.
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 the risks and benefits of this treatment with your doctor and family.
Because these cancers are often hard to treat, patients may want to consider taking part in clinical trials of newer treatments as well.
Last Medical Review: April 4, 2014 Last Revised: February 8, 2016
- Surgery for Gastrointestinal Stromal Tumor
- Ablation and Embolization to Treat Gastrointestinal Stromal Tumors
- Targeted Therapy for Gastrointestinal Stromal Tumor
- Chemotherapy for Gastrointestinal Stromal Tumor
- Radiation Therapy for Gastrointestinal Stromal Tumor
- Treatment Choices for Gastrointestinal Stromal Tumor Based on Tumor Spread