Gastrointestinal Stromal Tumor (GIST)


Patients diagnosed with gastrointestinal stromal tumors (GISTs) will benefit from a full understanding of the scope of the disease, including the results of diagnostic and pathology testing, surgical procedures, and medicinal therapeutics. The primary focus of patient education for GIST is to reinforce the necessity for lifelong clinical management due to the high likelihood of recurrence.1

Understanding GIST

GIST is a rare type of gastrointestinal tumor known as a sarcoma. GIST sarcomas develop in tissues that connect, support, or surround the internal organs and other body structures. GISTs usually develop in the wall of the stomach (60%) or small intestine (35%). GISTs rarely occur in the colon and rectum (5%), esophagus (1% to 5%), appendix (less than 1%), and other sites within the abdomen.2,3 These tumors develop within pacemaker cells that are responsible for maintaining the normal automatic movement of the gut. GIST develops either sporadically over time, or in rare cases, may be inherited from family members.  

Patient Adherence to Medications

It is important to adhere to taking the prescribed medications and understand proper dosing. Scheduling administration of the medication at routine times is important for optimal treatment outcomes. Patients must have an awareness of the gradual development of drug resistance due to gene mutations that may occur after starting a particular drug therapy. There may be a need to switch medications to a more effective one to slow disease progression.4 This aspect of GIST reinforces the necessity for the patient to schedule frequent clinical visits to perform imaging studies to assess treatment efficacy and disease progression. 

Patient Adherence to Follow-Up Recommendations

The current recommendation is for follow-up every 3 to 6 months for patients with GIST that has spread to other sites, keeps returning, or for those with high-risk GIST classification. Imaging via endoscopy or CT-scan may be performed every 6 to 12 months in individuals with low-risk GIST categorization.5 The oncologist must then decide if a change in therapeutic regimen is needed if the GIST growth has advanced despite current drug treatments based on the imaging results. Patient education must include the sequence of tyrosine kinase inhibitor (TKI) therapies to know that there are several available options which have obtained FDA approval for GIST treatment. This knowledge may decrease their uncertainty and reduce the sense of crisis that results from such uncertainty about their well-being.6 

Dietary Changes

Administration of imatinib (Gleevec) and other TKIs causes several side effects, one of which is reduction of calcium and magnesium levels in the blood. This may impact bone metabolism and result in muscle aches and cramping. Patients taking imatinib or other TKIs may need supplementation of calcium and magnesium as well as vitamin D which is needed to absorb calcium. Patients taking imatinib and sunitinib (Sutent) may demonstrate vitamin B-12 deficiency which may result from total or partial stomach removal surgery. These individuals may require B-12 injections or oral supplementation.7

One nutritional resource for patients with GIST who are seeking advice on dietary changes is an educational booklet called A Guide to Nutrition and Holistic Way of Living with GIST.8 This booklet also recommends supplementation of Vitamins A, B1, E, K, and zinc in addition to calcium, magnesium, Vitamin D, and Vitamin B12. It recommends avoidance of grapefruit as it interacts negatively with imatinib as well as avoidance of lying down or sleeping until 2 hours following a meal to reduce acid reflux. This booklet recommends avoidance of alcohol, processed and red meats, processed foods, tobacco, excessive coffee or tea, sugar, and heavy meals. It suggests eating smaller meals multiple times throughout the day instead of large meals. It is important to maintain a high fiber diet, drink plenty of water to aid in removal of toxins from the body, and eat at least 5 portions of fresh organic fruits and vegetables a day.8

Exercise

A Guide to Nutrition and Holistic Way of Living with GIST provides patients useful exercise tips. It encourages exercise for at least 30 minutes a day to improve muscle mass and tone, immune function, and overall fitness. GIST and sometimes the TKI medications used to treat GIST may cause weight loss and appetite changes which reduce muscle mass and tone. Exercise may counter this side effect of the disease and the medications used to treat it. Sustained physical activity such as brisk walking, swimming, pilates, yoga, cycling, dancing, aerobics, stair climbing, and jogging, in addition to other non-contact sports activities, may improve psychological well-being through release of endorphins. Daily exercise outside in sunlight improves Vitamin D levels. Vitamin D is known to have anticancer properties and improve bone growth. It is advised to keep a 6-month gap for starting exercises following abdominal surgery. Prior to resuming an exercise routine, always ask for physician approval.8 

Patient Resources

There are several patient-oriented organizations that provide resources for those newly diagnosed or managing chronic advanced GIST. These organizations include GIST Support International and the Life Raft Group. These organizations provide useful information regarding the disease, patient support groups, tips for caregivers, financial assistance to help pay for medications, and current treatment information including the drug development progression and clinical trials. 9,10  

References

  1. Choti, MA. Gastrointestinal stromal tumors (GISTs): patient education. Medscape. Published online April 3, 2021. Accessed June 28, 2021. 
  2. Hornick JL, Lazar AJF. Gastrointestinal stromal tumors: understanding your GIST pathology report. GIST Support International (GSI). Accessed June 28, 2021. 
  3. Understanding GIST – what is GIST? The Life Raft Group. Accessed June 28, 2021. 
  4. Wu C-E, Tzen C-Y, Wang S-Y, Yeh C-N. Clinical diagnosis of gastrointestinal stromal tumor (GIST): from the molecular genetic point of view. Cancers (Basel). 2019; 11(5):E679. doi:10.3390/cancers11050679
  5. Choti, MA. Gastrointestinal stromal tumors (GISTs) treatment and management: long-term monitoring. Medscape. Published online April 3, 2021. Accessed June 22, 2021.
  6. Macdonald N, Shapiro A, Bender C, Paolantonio M, Coombs J. Experiences and perspectives on the GIST patient journey. Patient Prefer Adherence. 2012; 6:253-262. doi:10.2147/PPA.S24617
  7. Proper nutrition for GIST cancer. The Life Raft Group. Accessed June 28, 2021.
  8. Guhagarkar N. A guide to nutrition and holistic way of living with GIST. Friends of Max. Accessed June 28, 2021.
  9. GSI: GIST Support International. GIST Support International. Accessed July 1, 2021.
  10. The Life Raft Group: patient. The Life Raft Group. Accessed July 1, 2021.

Article reviewed by Harshi Dhingra, MD, on July 1, 2021.

READ MORE ON GIST