What is GIST?
GIST means Gastrointestinal Stromal Tumor; it is a rare tumor of the gastrointestinal tract. It occurs most commonly in stomach (50–60 %); followed by small intestine (30–35 %) and less frequently in the colon/rectum, esophagus, mesentery, omentum, and retroperitoneum.
What causes GIST?
- The reasons are not so clear. Most cases are sporadic. These are caused by somatic mutations in genes like KIT and PDGFRA.
- Some are genetically acquired due to mutations in genes like SDH and NF1.
Is Gene mutation testing necessary?
- In non-metastatic disease (localized) mutation testing is done on surgical specimen. This helps doctors to understand how the cancer may behave and what type of treatment should be given, so that the patient may have less chances of disease recurrence.
- In metastatic disease mutation testing is done to select therapy. For example, if patient has a c-KIT mutation imatinib is used while those with a PDGFRA exon 18 D842V mutation, initial treatment should be with avapritinib rather than other TKIs as these patients are resistant to imatinib. Also, patients with SDH mutations are respond poorly to imatinib.
Is it enough to visit any Oncologist or it is necessary to see a specialist?
With the recent and considerable advances in management of GIST, it is better to meet a GIST specialist who can guide us properly and advise on the tests to be taken, so that patients may have access to best available treatment.
What is the main treatment involved?
- Surgery is the first option to get the tumor removed. After surgery, the risk of disease recurrence is calculated based on NIH/AFIP criteria (based on tumor size, proliferation rate and location of disease) and contour maps. If you are high risk, imatinib is prescribed to decrease chances of recurrence.
- When the cancer has spread to other organs, the medication imatinib may be prescribed.
How long the medication should be taken?
- After surgery, may be taken for three to five years; it will shrink the tumor or stop its growth.
- In advanced/metastatic disease, imatinib is taken till progression of disease upon which next line drugs are started.
Can the Cancer be cured?
If the medication works, it will stop its growth. But the drug may stop working with time, then there is a possibility of recurrence. At such time other drugs, as mentioned above can be started.
What if Imatinib does not work?
If the disease progresses on imatinib treatment, other drugs like sunitinib, regorafenib, avapritinib and ripretinib are available. The latter two drugs have been recently approved and are available under support program.
Are there any side effects for the drug?
Yes, common side effects are fatigue, nausea, body pain, difference in blood count and platelet count occurs. Your doctor will be monitoring you for these side effects. Most patients tolerate the drug well.
How is the cancer staged?
Staging is decided according to the location, size of the tumor and how fast the cancer is growing/multiplying (low or high) – accordingly it will be categorized as low, intermediate or high risk. If it has spread to other organs it is advanced/metastatic cancer.
Does Chemotherapy work for this?
Research shows that chemotherapy and radiation are not effective in the treatment of GIST
What kind of monitoring is needed?
CT Scan or PET Scan is recommended every 3-6 months by doctor to see the response. If the disease is decreased/or same size, same therapy is continued. If it increases, your therapy may be changed.
Will insurance pay for the drugs?
Many drug companies offer financial help or discount programs. For insurance, please check the policy documents which shows has the details of what is covered under cancer treatment.
Do we have any support groups in India?
Yes, we have the Sachin Sarcoma Society performing a wonderful job in connecting patients and doctors. Life raft group does the job in connecting patients internationally
What type of support do they give?
They connect us to the specific doctors, and they support emotionally by sending positive messages.
What type of attitude the patient should have?
Be positive. Be Happy. Find solace with the family members and caregivers and face the thing with the attitude “Cancer is Conquerable”. With new available treatment options and better care, most patient do well.
This article has been contributed by Dr. Sameer Rastogi, Dr. Saurav and GIST patient Arun Balakrishnan