18 Small Bowel Cancers and Gastrointestinal Stromal Tumors (GIST)

Benjamin R. Tan, Jr.

QUESTIONS

Each of the numbered items below is followed by lettered answers. Select the BEST answer(s).

Question 18.1 A 60-year-old previously healthy woman noted abdominal distension and discomfort for 6 months, associated with nausea and vomiting. Computed tomography (CT) scan shows a 20 × 25-cm abdominal mass, and exploratory laparotomy demonstrated a pedunculated mass arising from the stomach. No other metastases were found. A partial gastrectomy was done, and pathology revealed a gastrointestinal stromal tumor (GIST) which strongly stains for CD117 and CD34. Sixty mitoses were seen per 50 high-power field (HPF). Which of the following is TRUE regarding GISTs?

A. The most common mutation associated with GIST involves the inactivation of a tumor suppressor gene.

B. Both tumor size and mitotic index predict response to imatinib therapy.

C. Gastric GISTs are associated with relatively worse outcomes compared with small intestinal GISTs.

D. Patients with metastatic GIST tumors harboring exon 9 mutations have a better prognosis and response to imatinib compared with those with exon 11 mutation.

E. None of the above.

Question 18.2 After the patient in Question 18.1 has recovered from surgery, what would you recommend for this patient on the basis of current data?

A. Observation with serial scans

B. Imatinib 400 mg per os (PO) daily for 1 year

C. Imatinib 400 mg PO daily for at least 3 years

D. Sunitinib 50 mg 4 weeks on/2 weeks off therapy for 5 years

Question 18.3 A 52-year-old woman with metastatic gastric GIST had an initial complete response to daily imatinib 400 mg with resolution of her hepatic and peritoneal metastases after 6 months of therapy. Imatinib was continued for 18 months when her CT scan showed recurrent hepatic lesions. Imatinib was increased to 800 mg daily. However, subsequent scans revealed progressive disease. You recommend starting sunitinib for this patient. Which of the following statements are TRUE? (Select two correct responses)

A. Acquired resistance to imatinib therapy may be associated with the development of secondary KIT or PDGFRA mutations.

B. Sunitinib therapy for patients with imatinib-resistant GIST improved progression-free survival compared with placebo.

C. Patients with GIST harboring exon 11 mutation have a higher response to sunitinib than those with exon 9 mutation.

D. Patients with the wild-type GIST are resistant to both imatinib and sunitinib therapy.

Question 18.4 The patient in Question 18.3 started sunitinib 50 mg daily for 28 days followed by a 2-week break. After two cycles, repeated CT scans showed a decrease in the measurable lesions. In addition to hypopigmentation of her hair, she also noted progressive generalized fatigue. Patient denies any dyspnea on exertion, diarrhea, or pedal edema. Physical examination reveals an erythematous rash in the hands, clear lungs, no cardiac gallops or rubs, and no focal neurologic deficits. Pertinent laboratory tests are as follows:

White blood cell 5.6 × 103 cells/μL

Hemoglobin 11.8 g/dL

Sodium 145 mmol/L

Potassium 4.5 mmol/L

Creatinine 0.8 mg/dL

Total bilirubin 0.5 mg/dL

Alkaline phosphatase 118 μ/L

What would you order next?

A. Magnesium level

B. Magnetic resonance imaging of the brain

C. Thyroid function tests

D. 25-Hydroxycholecalciferol level

Question 18.5 After 6 months of sunitinib therapy, the patient in Question 18.4 was noted to have progression of her liver and omental lesions. Her Karnofsky performance status is 90% and hematologic, renal, and hepatic functions are all adequate. She is interested in further therapy. What would be your best recommendation?

A. No further therapy and proceed with hospice because there is no standard therapy after second-line sunitinib.

B. Sorafenib

C. Regorafenib

D. Bevacizumab

Question 18.6 Familial and genetic syndromes associated with GIST are: (Select two correct responses)

A. Cowden syndrome

B. Li–Fraumeni syndrome

C. Carney triad

D. Neurofibromatosis

Question 18.7 What is the most common type of small bowel malignancy?

A. Adenocarcinoma

B. Lymphoma

C. Carcinoid

D. Schwannoma

Question 18.8 Which of the following are characteristic of primary intestinal mucosal-associated lymphoid tissue (MALT) lymphoma? (Select two correct responses)

A. Association with Hashimoto thyroiditis

B. The majority of patients present with stages I and II

C. Most common in women

D. Associated with the translocation t(11;14)

Question 18.9 A 50-year-old male presented with bloating, and tarry stools. Upper endoscopy revealed a mass in the third portion of the duodenum, with the biopsy showing moderately differentiated adenocarcinoma. Resection demonstrated three periduodenal lymph nodes involved with carcinoma. CT scan showed no distant metastases. Which of the following statements regarding small bowel adenocarcinoma is TRUE?

A. The duodenum is the most common location for adenocarcinoma.

B. Jejunal and ileal tumors are associated with worse outcomes compared to duodenal adenocarcinoma.

C. Stage III small bowel adenocarcinoma is associated with a 63% survival.

D. Adjuvant therapy with irinotecan, 5-fluorouracil, and leucovorin is standard for stage III duodenal adenocarcinoma.

Question 18.10 Which of the following is a criterion to differentiate between primary intestinal and secondary lymphomas?

A. No superficial adenopathy

B. No evidence of splenic involvement except through direct extension of the primary tumor

C. No evidence of peripheral blood or bone marrow involvement

D. All the above

Question 18.11 The risk for progressive disease for a patient with small intestinal GIST measuring less than 2 cm with more than five mitoses/50 hpf is:

A. 0%

B. 4.3%

C. 24%

D. 50%

E. 85%

Question 18.12 A 20-year-old student presented to the emergency department with a 2-day history of right lower abdominal pain associated with fever. His abdomen was slightly distended with diffuse tenderness but without guarding or rebound tenderness. Rectal examination showed no masses and was negative for occult blood. Complete blood count showed a slightly elevated white blood cell at 11,000. CT scan showed a mass in the terminal ileum with no evidence of free peritoneal air. Colonoscopy revealed a terminal ileum mass, the biopsy of which showed sheets of monotonous round nucleated cells with abundant basophilic cytoplasm with numerous macrophages. Ki-67 index was 100%. What is your diagnosis?

A. MALT lymphoma

B. Burkitt lymphoma

C. Peripheral T-cell lymphoma

D. Medullary carcinoma of the small intestine

Related posts:

Cancer Prevention Molecular Biology of Cancer • Part 1 Esophagus and Stomach Cancer Ovarian Cancers Lymphomas Genetic Counseling

Stay updated, free articles. Join our Telegram channel

Join