Types of Treatment for Gastrointestinal Stromal Tumor

Executive Summary

Treatment recommendations depend upon the size, grade, and type of tumor, metastasis, possible side effects, and patient’s preferences and overall health. The significant factors contributing to determining the best treatment involve the size of the tumors, number of dividing cells, genetic makeup, primary location, whether it has already spread, and whether the tumor ruptured, either on its own or as a result of surgery. The common treatment for gastrointestinal stromal tumor also involves surgery, targeted therapy (Tyrosine kinase inhibitors (TKIs), Imatinib (Gleevec), Sunitinib (Sutent), Regorafenib (Stivarga), Larotrectinib (Vitrakvi), Avapritinib (Ayvakit), Ripretinib (Qinlock)), chemotherapy, and radiation therapy (external-beam radiation therapy, internal radiation therapy or brachytherapy). Palliative care includes medication, nutritional changes, emotional and spiritual support, and other relaxation therapies.

The stages of GIST also influence the suggested course of treatment. The localized GIST treatment includes surgery, neoadjuvant therapy, and metastatic GIST includes surgery, a higher dose of a TKI, or treatment through a clinical trial, recommendation of targeted therapy (regorafenib, imatinib, or sunitinib), and palliative care. 

Treatment of Gastrointestinal Stromal Tumor

“Standard to care” refers to the best-known treatment. In cancer care, different doctors work together to bring out an overall treatment plan for the patient. And so, a multidisciplinary team helps to determine the treatment. 

Treatment options and recommendations usually depend on several factors, including the type, stage and grade of cancer, possible side effects, and patient preferences and overall health.

The doctor will see many factors to determine the best treatment, including the tumours:

  • Size
  • Number of dividing cells
  • Genetic makeup
  • Primary location
  • Whether it has already spread
  • Whether the tumour ruptured, either on its own or as a result of surgery

Surgery

Surgery is the removal of the tumor and some surrounding healthy tissue during an operation. 

For people with localized GIST, surgery is the standard treatment. However, if the the gastrointestinal stromal tumor has metalized, a complete surgery and complete cure might not be possible ​1​. However, surgery may be effective only upto a certain limit.

Targeted Therapy

Targeted therapy aims at any factor contributing to the growth and development of cancer cells. It can be a specific protein, gene, or tissue environment. These treatments are typical and do not harm surrounding cells like those in chemotherapy or radiotherapy. However, all tumors do not have the same target. Hence, doctors may recommend testing to understand better changes in the individual tumor’s genes and proteins. This helps doctors match each patient with the most effective treatment possible. Additionally, research studies continue to find out more about specific molecular targets and new treatments directed at them.

Tyrosine kinase inhibitors (TKIs) target specific proteins called kinases that contribute to the tumor’s growth and survival ​2​. TKIs are often common in the treatment of gastrointestinal stromal tumor.

Even so, several factors influence the order.  Talk to the doctor about the possible side effects of each medication and how to make it more manageable.

Imatinib (Gleevec)

It was the first approved targeted therapy for GIST by the FDA. It is usually the first drug to treat GIST. Since it became available, the prognosis for patients with a GIST has improved a lot ​3​.

Research is going on to determine how long imatinib should be given post-surgery to help delay or prevent cancer comeback. And in fact imatinib is the only drug approved for use. If a GIST has spread to other body parts, imatinib will be for the rest of the patient’s life to help control the tumor.

The typical dose of imatinib is 400 milligrams (mg) daily. The dose may increase to 800 mg daily for some patients, especially those with an exon nine genetic mutation in the KIT gene.

Imatinib has some side effects, which are manageable. The dose can be adjusted to decrease side effects. It can also be in addition to other medicines to manage side effects. The common side effects of imatinib are rash, nausea, fluid accumulation, diarrhoea, fatigue, and minor muscle aches. Serious but relatively rare side effects can be bleeding and liver inflammation. Also, some side effects get better with time. Meanwhile, people who have severe side effects may take a lower dose of imatinib and benefit from it. 

Sunitinib (Sutent)

Sunitinib is a TKI that works in many different ways to slow tumor growth. it also blocks both KIT and makes new blood vessels, called angiogenesis. Hence, Sunitinib treats the gastrointestinal stromal tumor that grows even after imatinib treatment ​4​. Sunitinib may also also effective when the side effects of imatinib are too severe.

The side effects of sunitinib include fatigue, diarrhoea, nausea and vomiting, heartburn, changes in taste, high blood pressure, low blood counts, and changing skin color.

Regorafenib (Stivarga)

Regorafenib is a TKI that works in many different ways to slow tumour growth, including blocking the KIT molecule and blocking blood vessel growth into tumours. It was approved in 2013 for people with later-stage GIST that can’t be removed surgically and when both sunitinib and did not work or caused severe side effects.

The side effects of regorafenib include nausea, hand-foot syndrome, fatigue, high blood pressure, diarrhoea, and liver inflammation.

Larotrectinib (Vitrakvi)

A small percentage of sarcomas, less than 1%, have a mutation in the neurotrophic receptor tyrosine kinase (NTRK) gene. Larotrectinib (Vitrakvi) is an NTRK inhibitor now approved for any cancer with a particular mutation in the NTRK gene. These NTRK mutations are not found in the most common GIST types, including those with PDGFR, SDH, KIT, and RAF mutations.

The most common side effects include nausea, dizziness, vomiting, fatigue, increased liver enzymes, cough, constipation, and diarrhoea.

Avapritinib (Ayvakit)

Avapritinib is a TKI that targets tumors with a specific mutation in the platelet-derived growth factor receptor alpha (PDFGRA) exon 18 gene. It is also approved by the FDA to treat metastatic GISTs that have a mutation in PDGFRA exon 18 that can’t be removed with surgery.

The common side effects of avapritinib were swelling, nausea, fatigue, vomiting, loss of appetite, problems with attention, memory, or thinking, diarrhoea, hair colour changes, abdominal pain, constipation, increased production of tears from the eyes, rash, and dizziness.

Ripretinib (Qinlock)

Ripretinib is a TKI approved to treat an advanced GIST after three or more previous treatments with TKIs, including imatinib, have not stopped the tumour from growing and spreading.

The common side effects of ripretinib include fatigue, nausea, abdominal pain, hair loss, constipation, muscle pain, diarrhoea, loss of appetite, hand-foot syndrome, and vomiting. There is also a risk of severe side effects, including skin cancer, high blood pressure, and heart problems.

Chemotherapy

Chemotherapy uses drugs to destroy cancer cells, usually by keeping the cancer cells from growing, dividing, and making more cells. However, standard chemotherapy is not practical for treating GIST.

Radiation Therapy

Radiation therapy uses high-energy x-rays or other particles to destroy cancer cells. A doctor specializing in radiation therapy to treat cancer is a radiation oncologist. The most common radiation treatment type is external-beam radiation therapy. In this, the radiation given from a machine outside the body. And so, when radiation treatment is using implants, internal radiation therapy, or brachytherapy.

A radiation therapy schedule consists typically of a specific number of treatments offered over a set period.

Treatment for patients with gastrointestinal stromal tumours does not frequently involve radiation therapy. However, it may be a palliative treatment to relieve bone pain or stop bleeding. Radiation therapy may damage healthy cells along with tumor cells. Side effects from radiation therapy include mild skin reactions, upset stomach, tiredness, and loose bowel movements.

Palliative Care

Cancer and its treatment have side effects that can be mental, physical or financial and managing the effects are palliative or supportive care.

Palliative care includes medication, nutritional changes, emotional and spiritual support and other relaxation therapies. 

Palliative care focuses on alleviating how you feel during treatment by managing symptoms and supporting patients and their families with other non-medical needs. Regardless of type and stage of Cancer age, any person may receive this type of care.

Treatment by Stage of GIST

Each stage of a GIST may need a different course of treatment. The doctor will recommend a specific treatment plan for you based on the tumor’s stage and other factors. Clinical trials may also be a treatment option for each stage.

Localized GIST

A localized GIST is a tumor that has stayed in the part of the body where it began. Smaller localized GISTs may be entirely removed with surgery. This can be the only therapy necessary for some people. If the tumor is large or has spread to nearby organs, imatinib might be effective. This approach aims to shrink the tumor so it is easier to remove with surgery. This is the ‘neoadjuvant therapy.’

The surgeon will remove the entire tumor to reduce the risk of coming back or blocking the GI tract. The surgeon may have to remove parts of surrounding organs to remove the entire tumour, depending on the tumour’s location. Removing lymph nodes is not generally necessary because GISTs often do not spread to the lymph nodes. Lymph nodes are tiny, bean-shaped organs that fight infection. A tumour that cannot be removed using surgery is called ‘unresectable.’ The doctor will recommend targeted therapy for an unresectable localized GIST.

Gastrointestinal stromal tumor can come back after being surgically removed and spread to other organs. Some GISTs have a greater risk of spreading or returning than others. After surgery for a localized GIST, people who may have an increased risk of recurrence often receive imatinib for at least three years to help prevent or delay it from coming back. This type of treatment post-surgery is called ‘adjuvant therapy.’

Metastatic GIST

Doctors call it metastatic if a GIST has spread to another part of the body from where it started. If this happens, it is good to talk to doctors who have experience treating it. Doctors can have various opinions about the best treatment plan. Clinical trials can also be an option. 

In many instances, people with metastatic GIST can live everyday lives for many years, treated only with pills and regular hospital visits. 

Depending on previous treatment, the treatment plan can include surgery, a higher dose of a TKI, or treatment through a clinical trial. The doctor may continue to recommend regorafenib, imatinib, or sunitinib, even if they are not perfectly working. They may also suggest going back to 1 of these drugs (usual imatinib) after the others have been tried or after they have stopped working. In general, some treatment having targeted therapy for GIST is better than no treatment. Palliative care can also be essential to help relieve symptoms and side effects.

For most patients, a diagnosis of metastatic GIST is very stressful and challenging.

Remission and the chance of recurrence

Remission is when there are no more detectable traces of cancer or related symptoms in the body. This may also be known as having ‘no evidence of disease’ or ‘NED.’

Many people worry about the recurrence of cancer. A remission may be temporary or permanent. Many people worry about the recurrence of cancer.

Care and Concern

Recovery from bone sarcoma is not always possible. It is vital to have straightforward conversations with your health care team to express your feelings, preferences, and concerns. The health care team has unique skills, knowledge, and experience to assist patients and their families. Ensuring that a person is physically comfortable, free from pain, and emotionally supported is extremely important. 

References

  1. 1.
    Everett M, Gutman H. Surgical management of gastrointestinal stromal tumors: Analysis of outcome with respect to surgical margins and technique. J Surg Oncol. Published online December 12, 2008:588-593. doi:10.1002/jso.21030
  2. 2.
    Raut CP, Posner M, Desai J, et al. Surgical Management of Advanced Gastrointestinal Stromal Tumors After Treatment With Targeted Systemic Therapy Using Kinase Inhibitors. JCO. Published online May 20, 2006:2325-2331. doi:10.1200/jco.2005.05.3439
  3. 3.
    Demetri GD, von Mehren M, Blanke CD, et al. Efficacy and Safety of Imatinib Mesylate in Advanced Gastrointestinal Stromal Tumors. N Engl J Med. Published online August 15, 2002:472-480. doi:10.1056/nejmoa020461
  4. 4.
    Takaki H, Litchman T, Covey A, et al. Hepatic Artery Embolization for Liver Metastasis of Gastrointestinal Stromal Tumor Following Imatinib and Sunitinib Therapy. J Gastrointest Canc. Published online October 31, 2014:494-499. doi:10.1007/s12029-014-9663-2