Case Overview: A 68-Year-Old Man With GIST

Margaret von Mehren, MD: Today we’re going to talk about a case having to do with a patient with a gastrointestinal stromal tumor [GIST]. This is a 68-year-old gentleman who initially presented with a 5-month history of early satiety and vague abdominal pain. His past medical history was notable for hypertension, for which he was taking medications, and his blood pressure was well controlled. He had had a colonoscopy at age 55 that was unremarkable. And of note, his family history was negative for any sort of malignancy. On physical exam at the time of presentation, he had diffuse abdominal pain on palpation, but otherwise had no palpable masses or any other remarkable findings.

He had a clinical work-up that included laboratory testing, which showed a hemoglobin of 10.1 with a platelet level of 100. Otherwise, his laboratory findings were within normal limits, including liver function tests. He underwent an endoscopy that showed a submucosal mass measuring approximately 5 cm with evidence of ulceration. He then underwent an EUS-FNA biopsy [endoscopic ultrasound-guided fine-needle aspiration biopsy]. A mass with a regular border was seen on the extraluminal surfaces of the stomach, with evidence of heterogeneous echogenicity.

The biopsy from that lesion was consistent with GIST and showed a high mitotic rate of more than 5 mitoses per 50 high-power fields. He subsequently underwent a CT scan that confirmed a mass measuring 5.4 cm at the body of the stomach. And consistent with findings on an MRI, there was also evidence of peritoneal metastases. From the biopsy, mutational analyses were performed and he was found to have a KIT exon 11 mutation. At the time of his initial clinical work-up, he was healthy, well, and had an ECOG performance status of 0.

Having been found to have metastatic disease with an exon 11 mutation, he was initiated on imatinib dosed at 400 mg daily. He continued on that for a little over 2 years, at which time he was complaining of some increased abdominal pain and decreased appetite. His performance status was slightly decreased, and he was found to have progressive disease. His therapy was discontinued, and he was switched to sunitinib, taken as 50 mg daily for 4 weeks on, 2 weeks off, and he tolerated this well for approximately 9 cycles. Adverse effects that he noted were altered taste, occasional vomiting, and diarrhea, but, again, evidence of disease progression.

Then he was switched to third-line therapy with regorafenib 160 mg, which he took 3 weeks on, 1 week off, and tolerated with the exception of hand-foot syndrome. He continued on therapy until his disease progressed, and then he was initiated with ripretinib, 150 mg daily, orally.

Transcript edited for clarity.

Case: A 68-Year-Old Man With Gastrointestinal Stromal Tumor

Initial presentation

• A 68-year-old man complains of a 5-month history early satiety and vague abdominal pain
• PMH: hypertension, medically controlled; colonoscopy at age 55 unremarkable; no family history of cancer
• PE: diffuse abdominal pain on palpation; otherwise unremarkable
  
  

Clinical workup

• Labs: Hb 10.1 g/dL, plt 100 x 109/L; other lab values WNL
• Endoscopy: showeda submucosal ~ 5 cm mass with ulceration
• EUS-FNA biopsy: irregular borders on extraluminal surfaces of the stomach with evidence of heterogeneous echogenicity
• Biopsy showed gastrointestinal tumor with mitotic activity showed >5 mitoses/50 HPFs
• Abdominal/pelvic CT confirmed a 5.4 cm lesion in the body of the stomach
• MRI showed evidence of peritoneal metastases
• IHC and genetic mutational analysis: KIT exon 11 mutation
• ECOG 0
  
  

Treatment

• He was started on imatinib 400 mg PO qDay, continued for 26 months until he complained of increased abdominal pain and decreased appetite
  • ECOG 1; Imatinib was discontinued due to progressive disease
• Treatment with sunitinib 50 mg PO qDay for 4 weeks, with a 2-week drug-free interval was started
  • Treatment was well tolerated for 9 cycles when he developed an altered sense of taste, occasional vomiting and diarrhea; sunitinib was discontinued
• Regorafenib 160 mg (four 40 mg tablets) PO qDay for the first 21 days of each 28-day cycle was started and tolerated except for hand-foot syndrome
  • Regorafenib was discontinued on progression of disease
• The patient was started on ripretinib 150 mg PO qDay