The following article features coverage from the 46th Annual Oncology Nursing Society (ONS) Congress. Click here to read more of Oncology Nurse Advisor‘s conference coverage.

The significance of genetic evaluation of gastrointestinal stromal tumor (GIST) was discussed in a poster presented by Jennifer Propst, MS, CGC, of the Sarah Cannon Cancer Institute in Richmond, Virginia, at the 46th Annual Oncology Nursing Society (ONS) Congress.

GIST is a condition seen in some patients with type 1 neurofibromatosis (NF1). Prevalence of GIST is between 5% and 25% among patients with NF1, with NF1 itself believed to exist in 1 of every 3000 people. In cases of patients with both GIST and NF1, a phenotype may appear with tumors occurring more often in the small bowel than in the stomach. These tumors are typically negative for KIT and PDGFRA gene mutations, and they usually show poor response to imatinib, which is the usual treatment for sporadic GIST.

Ms Propst presented a case study involving a 43-year-old male patient who had experienced a month of gastrointestinal symptoms, including vomiting. An abdominal CT scan showed features that were suspicious for malignancy. After a small bowel resection, several T1N0 GISTs were found that were negative for KIT and PDGFRA mutations.

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The patient was referred to medical oncology and genetic counseling. He met 4 of 7 clinical criteria for NF1: a plexiform neurofibroma on his neck, 6 or more café au lait macules, freckling in axillary and inguinal regions, and what appeared to be a relevant family history of NF1 based on clinical features. The patient’s niece had a confirmed diagnosis of NF1 based on genetic testing.

The patient in this case study was initially placed on imatinib. After genetic and pathology results were reviewed, imatinib was discontinued. He is under surveillance with CT imaging at 6-month intervals and has not demonstrated progression.

In an audio recording accompanying her poster, Propst described several tumor types beyond GIST that appear to be more common with NF1. For example, women with NF1 show an increased risk of breast cancer before age 50, and approximately 10% of patients with NF1 will develop malignant peripheral nerve sheath tumors. “Being aware of genetic conditions that are associated with cancer and tumors is extremely important and can affect a patient’s surveillance and treatment for cancer,” Ms Propst concluded.

Read more of Oncology Nurse Advisor‘s coverage of the 46th Annual ONS Congress by visiting the conference page.


Propst JJ. NF1 related GIST. The importance of genetic diagnosis for treatment of GIST. Oncol Nurs Forum. 2021;48(2):abstr 9674.