Devita, Hellman, and Rosenberg's Cancer

LWBK1006-20 LWW-Govindan-Review December 12, 2011 19:4

Chapter 20•Cancer of the Gastrointestinal Tract 261

SECTION 4 SMALL INTESTINE AND GASTROINTESTINAL

STROMAL TUMORS

BENJAMIN R. TAN, Jr.

DIRECTIONS Each of the numbered items below is followed by lettered answers. Select the

ONE lettered answer that is BEST in each case unless instructed otherwise.

QUESTIONS

Question 20.4.1. A 60-year-old previously healthy woman noted abdominal distension and

discomfort for 6 months, associated with nausea and vomiting. A com-

puted tomography (CT) scan confirms a 20×25-cm abdominal mass,

and exploratory laparotomy demonstrated a pedunculated mass arising

from the stomach. No other metastases were found. A partial gastrec-

tomy was done, and pathology revealed a gastrointestinal stromal tumor

(GIST) that strongly stains for CD117 and CD34. Fifteen mitoses were

seen per high-power field (hpf). Which of the following is true regarding

GISTs?

A. The most common mutation associated with GIST involves the inac-

tivation of a tumor suppressor gene.

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

apy.

C. Gastric GISTs are associated with relatively worse outcomes com-

pared 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 20.4.2. After the patient in Question 20.4.1 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 to 2 years

C. Imatinib 400 mg PO daily for 5 years

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

Corresponding Chapters inCancer: Principles & Practice of Oncology,Ninth Edition: 86 (Cancer of the Small

Intestine) and 87 (Gastrointestinal Stromal Tumor).