By Lynne Eldridge, MD 

 Medically reviewed by Jay N. Yepuri, MD

Gastrointestinal stromal tumors (GIST) are a type of soft tissue sarcoma. While they are the most common type of digestive tract sarcoma, they account for only 0.2% of digestive tract cancers overall. They may be found anywhere in the digestive tract but are most common in the stomach and small intestine where they can cause bleeding, anemia, and sometimes severe pain when obstruction or perforation occur.

The diagnosis can be challenging, but is most often made with an endoscopic ultrasound. Treatment options (and subsequently survival) have advanced tremendously in recent years, and understanding of the genetic profile of these tumors is important in selecting the best approach.

Jose Luis Pelaez / The Image Bank / Getty Images

Types of GIST

GIST was only recognized as a distinct form of tumor a few decades ago, but advances in the genetic analysis of this tumor has led to progress in its treatment that can be considered a prototype of precision medicine (treating cancers individually based on their genetic make-up rather than with a one-size-fits-all approach).

Tissue Type/Classification

Gastrointestinal stromal tumors are classified as sarcomas, cancers that arise in connective tissues such as bone, cartilage, blood vessels, and nerve tissue. These tumors are often treated quite differently than the more common carcinomas, cancers that arise from tissues that line body cavities (such as the skin, lung, breast ducts, etc.)

It's currently believed that GISTs arise from cells called interstitial cells of Cajal (ICCs). These cells are part of the autonomic nervous system and are responsible for peristalsis (the waves of contractions that move food forward) in the digestive tract.¹

A GIST is most commonly diagnosed in adults between the ages of 40 and 70, but may be found in children. At one time it was thought that some GIST were benign (not cancerous) and some malignant (cancerous), but now it's thought that all GIST have the potential to spread (the hallmark of cancer). That said, most very small GISTs that begin in the stomach behave like benign tumors.²

Locations

Gastrointestinal stromal tumors may be found anywhere in the digestive tract, but are more common in some regions than others:¹

• Stomach: 60%

• Small intestine: 30%

• Duodenum: 5%

• Rectum: 3%

• Colon: 1%

• Esophagus: Less than 1%

• Other sites where GISTs uncommonly arise include the appendix, gallbladder, pancreas, retroperitoneum, and the tissues surrounding the pelvic organs in men and women.

Behavior

When GIST progress, they often advance locally and are less likely to spread (metastasize) to lymph nodes or distant sites compared with other cancers. When they do spread, the most common sites are the lungs and bones. The aggressiveness of these tumors can vary significantly, with up to 25% of stomach GISTs and up to 50% of small intestine GISTs being considered aggressive.¹

GIST Symptoms

The signs and symptoms of gastrointestinal stromal tumors are variable and non-specific and depend on where in the digestive tract the tumor begins.

Gastrointestinal Symptoms

In many cases, a GIST is discovered incidentally (accidentally) when an evaluation is done for another reason.

When present, possible symptoms may include:

• Bleeding (most common). This may include vomiting blood (hematemesis) or blood in the stool (melena). The blood may be red, dark brown, or black depending on where the bleeding occurs.

• Nausea and/or vomiting

• Abdominal pain (very severe with rupture)

• Loss of appetite

• Abdominal swelling or bloating

• Difficulty swallowing (dysphagia)

• Feeling full quickly with eating (early satiety)

• Anemia leading to lightheadedness (due to blood loss)

• Unintentional weight loss: A weight loss of 5% of body weight or more in a period of 6 to 12 months without trying should always be investigated.

• Fatigue

Complications

In some cases, the first signs and symptoms of a GIST may be related to complications of the tumor. These may include:

• Perforation: Perforation of the esophagus (perforated esophagus), stomach, or bowel (bowel perforation) may be the first symptom, and can cause severe pain.

• Obstruction: A bowel obstruction due to the presence of a tumor may cause severe pain and vomiting.

• Severe pain may be present even without complications of GIST.

Non-Gastrointestinal Symptoms

Non-digestive tract symptoms may be present in people who have familial GIST (GIST that runs in families or is associated with a genetic syndrome). People with familial GIST may also have more extensive symptoms, as multiple tumors are often present (people without a family history usually have a solitary tumor).

Additional symptoms may include dark patches on the skin, or raised, itchy, painful patches of brown skin.³

Incidence

The exact incidence of GIST is unknown, as it's thought that many of these tumors are misdiagnosed as other types of cancer. It's thought that roughly 5,000 cases are diagnosed in the United States each year. That said, small GIST are more common and often found incidentally when a workup is done for another reason. When autopsies have been done on adults who died from causes unrelated to GIST, small (less than 1 centimeter in diameter) GISTs have been found in over 20% of people.¹

Causes

Cancer most often begins when a series of mutations in two types of genes, oncogenes and/or suppressor genes, leads to the uncontrolled growth of a cell.

Tumor suppressor genes are genes that code for proteins that repair damaged cells or eliminate cells that can't repaired (so they can't go on and become a cancer). BRCA genes are examples of tumor suppressor genes.

Proto-oncogenes are genes that code for proteins that control the growth, division, and survival of cells, and are most active in a developing fetus. When mutated in adults (so that they continue to be in the "on" position), they are referred to as oncogenes. Two oncogenes, KIT and PDGFRA are responsible for roughly 85% of GISTs.⁴ Not all KIT or PDGFRA mutations are the same, and this is discussed below.

Tumor suppressor genes may also be affected in some people with GIST.

Risk Factors

GISTs are somewhat unique in that there are currently no known environmental or lifestyle risk factors for the disease. The disease is linked to age (being most common in middle age to older adults), but is similar among men and women and in different races.⁵

Gene Mutations and GIST

Most of the gene mutations responsible for the growth of GISTs are acquired or somatic mutations. These are in contrast to hereditary or germline mutations that are associated with hereditary cancers. With somatic gene mutations, the mutation develops sometime after birth in the process of a cell becoming a cancer cell.

When a cancer is related to a hereditary mutation, it is referred to as a hereditary cancer. In contrast, when a cancer is due to an acquired gene mutation, it is considered a sporadic cancer. KIT and PDGFRA gene mutations are associated with both hereditary and sporadic GISTs.³

Genetic Syndromes and GIST

A number of different genetic syndromes are associated with GIST. These include:

• Type-1 neurofibromatosis: This condition is associated with a mutation in the NF1 gene. Tumors associated with NF1 are found primarily in the stomach (60%) and small intestine (25%), and it's estimated that 3.9% to 25% of people with neurofibromatosis type 1 will develop a GIST at some point in their lifetime. People with this mutation often develop multiple GISTs along with tumors around nerves (neurofibromas) and multiple brown patches of skin (cafe au last spots).⁶

• Carney-Stratakis syndrome: Mutations in succinate dehydrogenase genes (SDHA, SDHB, SDHC, and SDHD) are associated with GIST as well as paragangliomas or pheochromocytoma. (A syndrome called Carney triad syndrome is similar, but instead of hereditary mutations in the genes is related to epigenetic changes in the genes.)⁷

• Primary familial GIST syndrome: While most GISTs harboring a KIT mutation are sporadic, there are some families who carry a hereditary mutation (autosomal dominant), frequently developing GISTs in late childhood.⁷

Diagnosis

The diagnosis of GIST begins with having a high index of suspicion as these tumors are often diagnosed as something else, and can be difficult to differentiate from benign tumors on tests such as endoscopy. They may be found incidentally or after investigating the symptoms they can cause.

Gastrointestinal stromal tumors vary widely in size from less than 1 centimeter (cm) (0.5 inches) to more than 40 cm. The average size at the time of diagnosis is 5 cm (roughly 2.5 inches) in diameter.¹

History and Physical

A careful history is important and includes a review of symptoms as well as a family history of GIST. Physical exam should look for abdominal tenderness, changes in weight, and signs associated with hereditary GIST such as cafe au lait spots.

Blood Tests

In addition to tests to identify the tumor, a complete blood count is done to look for evidence of anemia, as well as liver function tests as these tumors can sometimes spread to the liver.

Imaging Tests

Imaging tests are often done initially. This can include computed tomography (CT), magnetic resonance imaging (MRI), or positron emission tomography (PET), though CT is thought to be the best for identifying GIST.

The disadvantage of imaging tests is that a biopsy is not usually performed. With GIST, CT directed needle biopsy (percutaneous needle biopsy) is usually avoided due to both the risk of bleeding (these tumors bleed easily) and the risk of seeding the tumor (causing the spread of the tumor through traces of tumors that are left along the needle tract used to withdraw a biopsy sample).⁸

A PET scan may, however, be helpful in staging.

Procedures

Endoscopy, either EGD (esophagogastroduodenoscopy) or colonoscopy, uses a scope inserted either through the mouth or rectum to directly access a GIST. Since gastrointestinal stromal tumors usually grow under the surface layer of the intestine (mucosal layer), endoscopic ultrasound (using an ultrasound attached to the front of the scope) is often the best test for identifying these tumors. From the ultrasound, a guided fine needle biopsy can be done to determine how deep the tumor extends and to obtain a biopsy if needed.

Since part of the intestine (small intestine) can be difficult to see, there are a few options in addition to conventional endoscopy.

Capsule endoscopy is a procedure in which a capsule containing a small camera is swallowed. The camera can take pictures as it travels through the small intestine (a process that usually takes roughly eight hours) and transmits the images to an external device a person wears on their body like a belt. The camera passes normally with a bowel movement and does not need to be retrieved. A disadvantage of capsule endoscopy is that a biopsy cannot be done with the procedure.¹

Another option for accessing difficult to reach areas of the intestines, while also allowing for a biopsy, is double balloon enteroscopy. this procedure involves inserting two endoscopy tubes, with one inside of the other. The tubes are slowly inched forward by advancing one tube and then the other in a periscope fashion, beginning with a tube inserted either through the mouth or rectum.

Biopsy

A biopsy may be done either through the skin, via an endoscopic ultrasound, or with a surgical biopsy (at the time of surgery to remove a tumor). With any of these procedures the risk of bleeding must be considered as GISTs are usually very friable (break apart very easily).

A biopsy is not always needed if surgery will be performed, as in this setting a biopsy can be done later. With inoperable tumors, however, a biopsy can be very important, as testing to determine the specific mutations present can help guide treatment.

A biopsy sample is used to note the characteristics of a tumor under the microscope, evaluate the mitotic rate, and perform histochemistry analysis and genetic testing.

The mitotic rate is important in determining the aggressiveness of a GIST and is described as being greater or less than five mitotic cells per high power field. Mitotic cells are cells that are noted to be in the active stage of cell division.

Molecular/Genetic Analysis

In addition to checking the mitotic rate, techniques including immunohistochemistry, immunostaining, and genetic profiling may be done. In order to understand these tests, it's helpful to look at what mutations may be present, as this helps healthcare providers determine the best treatment for an individual tumor.

It's currently recommended that everyone with a GIST be tested for KIT and PDGFRA mutations. If negative, testing for BRAF, SDH, and NF1 should be undertaken.⁹

GIST Mutations

The most common mutations found in GIST are KIT and PDGFRA mutations:

KIT mutations are present in around 80% of GISTs.³ Mutations, however, may occur in different regions of the gene, and how tumors respond to treatment can vary depending on whether the location is, for example, in exon 11 (most common), exon 9, exon 13/14, exon 17/8, etc.

PDGFRA mutations are found in roughly 10% of these tumors (and involve exon 12 or 18).³ Most of these mutations respond in a similar way to treatment with the exception of D842V.

Tumors that do not harbor a KIT or PDGFRA mutation are sometimes referred to as "KIT-PDGFRA wild-type tumors" and account for roughly 10% to 15% of these tumors (but a higher percentage in children and young adults). These tumors may also harbor gene mutations that may guide treatment. Examples include:

• SDH genes: These tumors tend to occur in younger people, and unlike typical GISTs, may spread to lymph nodes. Fortunately, they are usually slow-growing tumors.¹⁰

• NF1

• BRAF mutations: These tumors are frequently in the small intestine.

• KRAS mutations

• NTRK gene fusions

• Other subtypes have also been noted, such as fusions involving the NTRK or BRAF gene.

Immunohistochemistry

Immunochemistry is a special staining technique done that looks for specific proteins on the surface of cancer cells. Roughly 95% of GISTs will stain positive for CD117 (CD117 is the protein coded for by the KIT gene), and 80% positive for CD34 or DOG1. Tumors that are positive for both CD117 and DOG1 have a 97% chance of being a GIST.⁴

CD117 isn't specific for GIST, and may be positive with some other types of sarcoma. Other immunostaining techniques are helpful in some cases.

Genetic Profiling

Genomic testing such as next-generation sequencing can reveal further details about KIT and PDGFRA mutations, and is helpful as tumors with mutations at different places in these genes can affect how a person will respond to treatment.

Molecular profiling is also helpful in identifying less common mutations, which is important as these tumors do not often respond to the most common treatments for GIST. In one study, mutations were found in 82% of tumors that tested negative for KIT and PDGFRA.¹¹

Differential Diagnosis

A number of conditions need to be distinguished from a GIST, and can lead to similar symptoms. These include:

• Leiomyoma or leiomyosarcoma

• Schwannoma

• Peritoneal mesothelioma

• Peripheral nerve-sheath tumor

• Solitary fibrous tumor

• Synovial sarcoma

• Neuroendocrine tumors such as carcinoid tumors

• Fibromatosis

• Inflammatory myofibroblastic tumors

• Gastric glomus tumor

• Angiosarcoma

• Sarcomatoid carcinoma¹

Staging

Unlike many cancers that are staged from stage 1 to stage 4 in order to determine the best treatment options, GISTs are described primarily based on clinical features. These include:

• Tumor location

• Tumor size

• Mitotic index (greater than or less than 5 mitoses per high power field)²

GISTs are more likely to spread if they are larger (greater than 2 cm or roughly 1 inch in diameter), if they are located somewhere other than the stomach or omentum, and/or if they have a high mitotic index.

When staging to define treatment options, GISTs are broken down into two categories:

• Resectable (operable) tumors: These are tumors that can be removed surgically.

• Unresectable (inoperable) tumors: Some tumors cannot be treated effectively with surgery due to their location or because the tumor has already spread beyond the digestive tract.

A separate staging approach divides GISTs into two categories based on the location of the tumor.

• Tumors involving the stomach or omentum: These tumors are less likely to grow fast or spread to other regions.

• Tumors involving the small or large intestine, the esophagus, or peritoneum. These tumors tend to grow more rapidly and are more likely to spread.

Staging tests may include CT, MRI, PET, chest X-ray, or bone scan depending on the characteristics of the tumor.

Treatment

Treatment options for GIST may include surgery, surgery followed by targeted therapy for a period of time (adjuvant therapy), targeted therapy before surgery (neoadjuvant therapy), a targeted therapy medication alone, or watchful waiting. Several clinical trials are also in progress.

Chemotherapy is not thought to be effective for GIST, and radiation therapy is primarily reserved for complications or metastases in some cases. Here is how different stages are usually addressed:

• Very small, Incidental tumors: Watchful waiting or active surveillance (carefully monitoring a tumor but holding off on treatment) may be considered with some very small GISTs. Most tumors, however, have larger than this at the time of diagnosis. This is primarily an option for people who have GISTs that are less than 1 to 2 centimeters in diameter, and when the tumor is found incidentally when surgery is performed for another reason. Watchful waiting does not mean ignoring a treatment, and these tumors will require careful follow-up.

• Resectable tumors: The treatment of choice, when possible, is surgery. For tumors that have a high risk of recurrence, targeted therapy is usually recommended following surgery.

• Unresectable tumors: Tumors that cannot be removed with surgery for some reason are treated as metastatic GIST. After a period of time, however, these tumors may shrink to a degree that surgery is then possible.

• Metastatic tumors: Metastatic GISTs are treated with targeted therapy, and mutation testing is very important to determine the best options.

Surgery

Surgery may be used in three different settings with GISTs:

• Tumors that are resectable (are small enough and haven't spread so that they can be surgically removed)

• Unresectable tumors that have shrunk sufficiently with targeted therapy

• Palliative surgery used to control complications of these tumors such as bleeding

Surgery for GISTs differs somewhat from other cancer surgery procedures. Since these tumors do not spread far within the muscle, major surgeries (such as removing the whole stomach) are not usually needed. Surgery is designed to remove the tumors such that no cancer cells are present on the edges of the tissue to be removed (negative margins if possible). Even if some tumor is present on the margins, re-surgery is not usually done.

Surgery can be done via either minimally invasive surgery (such as a laparoscopy) or via an open procedure (eg. a laparotomy). Laparoscopy is preferred, especially in older patients, and can often be used with tumors that are 5 cm in diameter and smaller.

Removal of lymph nodes is also not usually needed, as most of these tumors do not tend to spread to lymph nodes (an exception is GIST with SDH mutations in which enlarged nodes should be removed).

It's very important to have a surgeon who is experienced in GIST surgeries. The surgeon needs to be careful not to disrupt the outer lining around the tumor (pseudocapsule) due to the risk of bleeding and also because it could promote the spreading of the tumor.²

Surgery Plus Adjuvant Targeted Therapy

With surgery, targeted therapy may be used either before surgery or after surgery.

Adjuvant therapy refers to the use of targeted therapy after surgery to reduce the risk of recurrence. It's now recommended that people with tumors that have a high risk of recurrence (based on tumor size, location, etc.) be treated with targeted therapy for at least 3 years following the surgery, though there is some thought that this might be continued longer, especially for people who have tumors with KIT exon 11 mutations.¹²

Neoadjuvant therapy refers to the use of targeted therapy (Gleevec) before surgery to reduce the size of a tumor. This can sometimes result in a much less invasive surgery. Other times, a tumor that is previously inoperable may become operable after a period of using targeted therapy. In this setting, the targeted therapy is usually used for around 2 years before surgery is performed.¹³

Radiofrequency ablation is sometimes used as an alternative to surgery when surgery would be too risky for some reason (due to advanced age, etc.).

Targeted Therapy: KIT and PDGFRA

Targeted therapies are medications that target cancer cells or specific pathways involved in the growth of a cancer. Since they are designed to target a cancer specifically, they often (but not always) have fewer side effects than chemotherapy drugs.

Since targeted therapies interfere with a pathway critical to the growth of a tumor, they are often very effective (at least for a period of a year or more). They do not, however, cure a cancer, and these tumors often recur once treatment is stopped.

For people with unresectable or metastatic GIST, targeted therapy is usually the treatment of choice. It is also often recommended as adjuvant or neoadjuvant therapy.

Gleevec (Imatinib)

Gleevec is the first drug usually used, and is effective with most tumors that are positive for KIT or PDGFRA mutations (it targets the proteins coded for by these genes). Gleevec may be started right away with advanced tumors or in cancers where surgery may someday be possible but is currently not recommended. It may also be started after surgery in cancers that have a significant risk of returning.

When Gleevec is first started, people are cautioned to watch for any signs of digestive tract bleeding, as these tumors can sometimes bleed if they shrink rapidly. The most common side effects are rashes, diarrhea, abdominal pain, and muscle aches and pains.

Exceptions: Some GISTs are less likely or unlikely to respond to Gleevec. These include tumors with:

• KIT exon 9 mutations: Only about half of these tumors respond to Gleevec (38% in one study), but may respond to higher doses (eg. 800 milligrams instead of 400 milligrams) and it's recommended that people be started on this higher dose or instead be started on Sutent.

• KIT exon 13 and exon 14 mutations are usually started on Sutent.⁸

• KIT exon 17 mutations may be started on Iclusig (ponatinib) instead of Gleevec.⁸

• PDGFRA D842V: Tumors with this mutation do not respond to Gleevec. According to guidelines, a clinical trial with a PDGFRA D842V inhibitor such as Crenolanib may be the best choice, when available.¹⁴ These tumors may also respond to the targeted medication Sprycel (dasatinib).¹⁵

• PDGFRA exon 18 mutations tend not to respond to first-line therapies, and are often started on Ayvakit (avapritinib).⁵

• Other mutations (eg: SDH, NF1, etc.): For "wild-type" tumors, a different treatment or clinical trial is usually recommended (see below).

When Gleevec stops working (the average time is two years), there is a choice to either double the dose of the medication or switch to Sutent.

Sutent (Sunitinib)

Sutent is another targeted therapy that is often used second-line for GIST (other than those noted under exceptions above). Side effects include nausea, diarrhea, mouth sores, and skin changes, as well as the risk of serious bleeding and high blood pressure in some people.

Stirvarga (Regorafenib)

Stivarga is usually recommended third line, when both Gleevec and Sutent stop working. Side effects are similar to Stutent, and Stivarga also carries the uncommon risks of bleeding, intestinal perforation, and blistering of the hands and feet.

Qinlock (Ripretinib)

When the first three medications above stop working, Qinlock is now often recommended fourth line for treatment (or a clinical trial with another medication).

Other Options

For tumors that are not responding to the above medications, other options (some only available in clinical trials) may include:

• Nexavar (sorafenib)

• Tasigna (nilotinib)

• Sprycel (dasatinib)

• Votrient (Pazopanib)

• Iclusig (ponatinib)

• Mektovi (binimetinib)

• crenolanib

How Long Should Treatment Continue?

When a tumor is controlled on Gleevec, many people wonder how long the medication should be continued. Unfortunately, if treatment is stopped, even after a complete response, there is a high risk of progression.

Fortunately, and unlike cancer treatment with a number of different targeted therapies, most people who stop and then restart their medication will again respond. For this reason, it's usually recommended that targeted therapy be continued until a tumor progresses even if any metastatic tumors have been removed.¹⁶ Even if a tumor is progressing, stopping targeted therapies can result in more rapid growth of the tumor as well.

Is Surgery Possible?

In some people with metastatic GIST who respond to Gleevec, treatment with cytoreductive surgery following Gleevec may be an option. In one study, 78% of people who received this surgery had no evidence of disease after surgery, and overall survival was 95%.¹⁴

Targeted Therapy: Wild-Type Tumors

Tumors with mutations in genes other than KIT and PDGFRA do not usually respond to conventional targeted therapies for GIST. That said, a 2020 study estimates that roughly 20% of tumors that initially test negative for KIT and PDGFRA mutations are actually carriers of KIT mutations and might, therefore, respond to the treatments above for these tumors. The researchers recommend that a second-level molecular analysis (gene profiling) be done on tumors that initially test negative.¹⁷

SDH Mutations

These tumors tend to occur in younger people, more often in women, and unlike other GISTs, tend to spread early and to lymph nodes. That said, they tend to grow more slowly. Most of these tumors are resistant to Gleevec, and surgery is the mainstay of treatment at the current time.¹⁸

NF1

Genomic sequencing is very important for people who have tumors with a NF1 alteration (alteration is a term that's used to describe both mutations and other changes in genes leading to cancer). While tumors "driven" by NF1 alterations do to respond to Gleevec, some of these tumors also have KIT mutations and may respond, especially those that occur in one specific area of the small intestine.¹⁹

BRAF

GISTs that harbor BRAF mutations may respond to the currently available BRAF inhibitors used for melanoma and other cancers.²⁰

NTRK Gene Fusion

Roughly 1% of GISTs may harbor a neutrophil receptor kinase (NTRK) gene fusion. The medication Vitrakvi (larotrectinib) is now approved for any type of cancer that contains this mutation, and good responses have been seen with some soft tissue sarcomas.²¹ Clinical trials are also currently in place studying drugs such as Loxo-195 and TPX-0005.

Recurrence and Progression

Recurrence is far too common with GISTs that are treated with surgery, and these tumors may recur in the digestive tract, or at distant sites such as the liver, abdomen, or peritoneum. With distant recurrence, a tumor is then treated as a metastatic tumor, usually with targeted therapy.

Follow up for people who have tumors with a high risk of recurrence is often done with serial CT scans (such as an abdominal and/or pelvic CT scan every three to six months).¹

When tumors progress, the next available targeted therapy is often used. With a distant progression (metastasis), sometimes local treatment is used in addition to the targeted therapy.

Treatment of Metastases

Sometimes metastases occur (such as to the liver) in people who are otherwise responding to targeted therapy. When this occurs, local treatment of the metastasis can sometimes result in control of the tumor. Ablation (radiofrequency ablation) or arterial embolization procedures are most often used.

With many types of cancer, a treatment is discontinued when the cancer progresses while on that treatment. With GISTs, however, this is not recommended as stopping a medication may lead to the more rapid growth of the tumor

With advanced GISTs that are progressing on a tyrosine kinase inhibitor, the medication is usually continued as these cancers may progress more rapidly if the treatment is stopped.

Clinical Trials

With many GISTs, a clinical trial may be a good option. In addition to the targeted therapies discussed above, some of the therapies that are being studied include:

• Immunotherapy drugs: Opdivo (nivolumab) and Yervoy (ipillimumab)

• Monoclonal antibody SmAb18087

• Endoscopic ultrasound alcohol ablation⁸

Prognosis

The prognosis of a GIST includes many factors such as the size of the tumor when diagnosed, the mitotic rate, the location of the tumor, whether the tumor has spread, and whether the tumor can be removed with surgery. KIT and PDGFRA positive tumors seem to have a similar prognosis.

SEER data looking at people who were diagnosed between 2009 and 2015 show an overall five-year survival rate of 83%, with a rate of 94% with localized disease, 82% with regional disease, and 52% with distant disease. But new treatments have been adopted since that time.²²

For those who are diagnosed, this is one type of cancer for which treatments and survival rates have improved significantly in recent years, even with metastatic disease. The 2-year survival rate for people with metastatic GISTs who are treated with Gleevec is now 80% from the time of metastasis.²³

Coping

It is frightening enough to be diagnosed with cancer, but when you learn you have a cancer most people aren't familiar with, it can be even more frightening. Fortunately, there are now many treatment options available for most of these tumors.

Learn About Your Tumor

The downside of having many treatment options, is that people are being called on to make more decisions with regard to their care. Taking time to research your cancer can not only help you feel more in control of your journey, but in some cases, can even affect outcomes. It's important to look at recent information, however, as the treatment as well as survival rates for the disease are improving rapidly.

Find a Good Cancer Care Team

For those who have uncommon cancers, it's very helpful to find a healthcare provider who specializes in that type of cancer. With advances occurring in so many areas of oncology, it's difficult to stay on top of one type of cancer, not to speak of all types of the disease.

Getting a second opinion at a National Cancer Institute-designated treatment center is one good way to do this, and doesn't necessarily mean you will need to travel. Many of these centers are now doing remote consults, and can sometimes work with your healthcare provider at home to design a treatment plan.

Support

The importance of support can't be overstated when you are coping with cancer. This doesn't mean that you have to broadcast your tumor to everyone you know, but having a core group of people you can talk with, and who are willing to jump in and help, is crucial.

Support from others coping with the same disease can also be priceless, both for social support and to learn more about your tumor. The internet is a great way to connect with others when you are facing an uncommon cancer. As a plus, many of the support groups for uncommon cancers are "deeper" than the large groups for people with common cancers, and it's not uncommon to form lifelong friendships with some of the people you meet. Some options are:

• GIST Support International support groups

• CancerCare GIST patient support community

• The LifeRaft group: This group provides one-on-one mentoring, support groups, and even helps people learn about financial help.

• Facebook: Several groups are available, including private groups

• Twitter: You can find both people living with GIST and those researching the disease by searching the hashtags #GIST, #gastrointestinalstromal tumor, #GISTtumor, and #sarcoma.

23 Sources

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Chen HW, Chen TWW. Genomic-guided precision therapy for soft tissue sarcoma. ESMO Open. 5(2):e000626. doi:10.1136/esmoopen-2019-000626

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Joensuu H, Wardelmann E, Sihto H, et al. Effect of KIT and PDGFRA nutations on survival in patients with gastrointestinal stromal tumors treated with adjuvant imatinib: An exploratory analysis of a randomized clinical trial. JAMA Oncology. 2017;3(5):602-609. doi:10.1001/jamaoncol.2016.5751

Ishikawa T, Kanda T, Kameyama H, Wakai T. Neoadjuvant therapy for gastrointestinal stromal tumor. Translational Gastroenterology and Hepatology. 2018. 3:3. doi:10.21037/tgh.2018.01.01

Povedaa A, del Murob XG, Lopez-Guerreroc JA, et al. GEIS guidelines for gastrointestinal sarcomas (GIST). Cancer Treatment Reviews. 2017;55:107-119. doi:10.1016/j.ctrv.2016.11.011

Szucs Z, Thway K, Fisher C, et al. Promising novel therapeutic approaches in the management of gastrointestinal stromal tumors. Future Oncology. 2017;13(2):185-194. doi:10.2217/fon-2016-0194

Ogata K, Kimura A, Nakazawa N, et al. Long-term imatinib treatment for patients with unresectable or recurrent gastrointestinal stromal tumors. Digestion. 2018;97:20-25. doi:10.1159/000484102

Astolfi A, Indio V, Nannini M, et al. Targeted deep sequencing uncovers cryptic KIT mutations in KIT/PDGFRA/SDH/RAS-P wild-type GIST. Frontiers in Oncology. 2020;10:504. doi:10.3389/fonc.2020.00504

Ibrahim A, Chopra S. Succinate dehydrogenase-geficient gastrointestinal stromal tumors. Archives of Pathology and Laboratory Medicine. 2020;144(5):655-660. doi:10.5858/arpa.2018-0370-RS

Burgoyne AM, De Siena M, Alkhuziem M, et al. Duodenal-Jejunal Flexure GI Stromal Tumor Frequently Heralds Somatic NF1 and Notch Pathway Mutations. JCO Precision Oncology. doi:10.1200/PO.17.00014

Huss S, Pasternack H, Ihle MA, et al. Clinicopathological and Molecular Features of a Large Cohort of Gastrointestinal Stromal Tumors (GISTs) and Review of the Literature: BRAF Mutations in KIT/PDGFRA Wild-Type GISTs Are Rare Events. Human Pathology. 2017. 62:206-214. doi:10.1016/j.humpath.2017.01.005

Drilon A, Laetsch TW, Kummar S, et al. Efficacy of larotrectinib in TRK fusion–positive cancers in adults and children. New England Journal of Medicine. 2018;378(8):731-739. doiI:10.1056/nejmoa1714448

American Cancer Society. Survival rates for GIST tumors.

Call JW, Wang Y, Montoya D, et al. Survival in advanced GIST has improved over time and correlates with increased access to post-imatinib tyrosine kinase inhibitors: results from Life Raft Group Registry. Clinical Sarcoma Research. 2019;9:4. doi:10.1186/s13569-019-0114-5

Additional Reading

American Cancer Society. Targeted drug therapy for gastrointestinal stromal tumors.

Casali PG, Abecassis N, Aro HT, et al. Gastrointestinal stromal tumours: ESMO-EURACAN clinical practice guidelines for diagnosis, treatment and follow-up. Annals of Oncology. 2018;29(Suppl 4):iv68-iv78. doi:10.1093/annonc/mdy095

Jakob J, Hohenberger P. Neoadjuvant therapy to downstage the extent of resection of gastrointestinal stromal tumors. Visceral Medicine. 2018;34(5):359-365. doi:10.1159/000493405

Joensuu H, Eriksson M, Hall KS, et al. One vs three tears of adjuvant imatinib for operable gastrointestinal stromal tumor a randomized trial. JAMA. 2012;307(12):1265-1272. doi:10.1001/jama.2012.347

Joensuu H, Vehtari A, Riihimaki J. Risk of recurrence of gastrointestinal stromal tumour after surgery: an analysis of pooled population-based cohorts. Lancet. 13(3):265-274. doi:10.1016/S1470-2045(11)70299-6

Kalfusova A, Linke Z, Kalinova M, et al. Gastrointestinal stromal tumors - summary of mutational status of the primary/secondary KIT/PDGFRA mutations, BRAF mutations and SDH defects. Pathology Research and Practice. 2019;215(12):152708. doi:10.1016/j.prp.2019.152708

Menge F, Jakob J, Kasper B, et al. Clinical presentation of gastrointestinal stromal tumors. Visceral Medicine. 2018;34:335-340. doi:10.1159/000494303

Nishida T, Blay JY, Hirota S, et al. The standard diagnosis, treatment, and follow-up of gastrointestinal stromal tumors based on guidelines. Gastric Cancer. 2016;19(1):3-14. doi:10.1007/s10120-015-0526-8

U.S. National Library of Medicine. Genetics Home Reference. KIT gene.

By Lynne Eldridge, MD
 Lynne Eldrige, MD, is a lung cancer physician, patient advocate, and award-winning author of "Avoiding Cancer One Day at a Time."