Board Preparation: Leukemia, Sarcoma

Oct 24, 2016

Test your knowledge of leukemia and sarcoma to assist your preparations for Board examinations with questions from a past edition of ASCO-SEP®, ASCO’s self-evaluation program in oncology.

The new fifth edition of ASCO-SEP is available for purchase in the ASCO University® bookstore. Featuring 21 updated chapters and more than 180 new self-assessment questions in the book, as well as a 120-question comprehensive mock exam online, this resource is perfect for Board preparation, and can be used to earn Maintenance of Certification and continuing medical education credit. Visit university.asco.org for information about the latest edition of ASCO-SEP and other self-assessment resources.

Correct answers, rationales, and suggested reading are listed at the bottom of the page.

 

  1. A 58-year-old otherwise fit man presents with fatigue. On physical examination, a 2-cm non-tender cervical lymph node is detected in his right neck; the exam is otherwise normal. A complete blood count shows a white blood cell count of 96,000/mm3, of which more than 90% are mature-appearing lymphocytes with occasional prolymphocytes. His hematocrit is 43% and his platelet count is 372,000/mm3.

    An appropriate work-up for this individual would include which of the following?
     

A. Studies of the peripheral blood for immunophenotype, immunoglobulin (Ig) heavy chain status, and fluorescence in situ hybridization (FISH) for 11q, 13q, and 17q  
B. Bone marrow aspiration and biopsy for morphology, and studies of immunophenotype, Ig heavy chain status, and FISH for 11q, 13q, and 17q  
C. Studies of peripheral blood for immunophenotype, Ig heavy chain status, and FISH for 11q, 13q, and 17q, as well as bone marrow aspiration and biopsy for morphology
D. Bone marrow aspiration and biopsy for morphology and studies of immunophenotype, Ig heavy chain status, and FISH for 11q, 13q, and 17q, as well as a lymph node biopsy   

 

  1. A 54-year-old previously healthy man presents with severe fatigue, shortness of breath on exertion, and pallor. Routine blood testing reveals hemoglobin of 6 gm/dL and mean cell volume of 74 fL. Serum ferritin is less than 10 ng/mL. Endoscopy identifies an ulceration in the stomach but mucosal biopsy is nondiagnostic. CT of the abdomen and pelvis reveals a 12-cm enhancing, vascular mass arising from the gastric fundus, but is otherwise normal.

    The patient undergoes partial gastrectomy and the mass is removed intact. The pathologist reports the presence of a gastrointestinal stromal tumor (GIST), 11 cm in greatest dimension, 4 mitoses per 50 high-power microscopic fields (HPF) of view, the presence of CD117 (KIT) and CD34, and absence of desmin on immunohistochemistry. Molecular testing detects a deletion in exon 11 of KIT. Surgical margins are reported as close but negative. Imatinib at a dose of 400 mg daily for 3 years is recommended as adjuvant therapy.

    The effect of 3 years compared with 1 year of imatinib in patients with resected high-risk GIST in a randomized trial demonstrated which of the following?
     

A. Delay in time to tumor recurrence, but no difference in overall survival
B. Improvement in overall survival at 5 years, but no improvement in recurrence-free survival
C. Improvement in recurrence-free and overall survival at 5 years
D. No difference in recurrence-free or overall survival

 

Rationales

1: A

This patient likely has chronic lymphocytic leukemia (CLL). Immunophenotyping of the peripheral blood is required to establish the diagnosis. Typically, the cells will be positive for the B-cell markers CD19, CD20, and CD23, and the T-cell marker CD5. This helps to distinguish the disease from mantle cell lymphoma, which does not express CD23, and T-cell prolymphocytic leukemia, which expresses additional T-cell markers.

Since the patient is symptomatic, he will likely be offered therapy for his disease. Thus, additional tests are useful to help select therapy and provide prognostic information. Ig heavy chain status is a useful prognostic factor, with more aggressive disease associated with unmutated heavy chain status. A FISH panel for abnormalities of 11q, 13q, and 17q not only provides prognostic information, but may help in the selection of therapy. Abnormalities of 13q are associated with a more favorable prognosis, whereas abnormalities of 11q and 17q are associated with more aggressive disease. For patients with 11q and 17q abnormalities, more aggressive regimens like fludarabine/cyclophosphamide/rituximab are recommended.

A bone marrow examination might provide useful information if the patient had a significant cytopenia. Neither CT scan nor lymph node biopsy is indicated.

Suggested Reading
Döhner H, Stilgenbauer S, Benner A, et al. Genomic aberrations and survival in chronic lymphocytic leukemia. N Engl J Med. 2000;343:1910-1916. PMID: 11136261.

 

2: C

A randomized trial of 1 year versus 3 years of imatinib at a dose of 400 mg daily following resection of a high-risk GIST demonstrated improvement in recurrence-free survival and overall survival rates. High risk is defined as tumor size larger than 10 cm or tumor mitotic count higher than 10 per 50 HPF of view, or tumor size of 5 cm to 10 cm and mitotic count of 5 to 10 per 50 HPF of view, or rupture of tumor.

At 5 years from study entry, 66% of the patients receiving imatinib for 3 years compared with 48% of the patients receiving imatinib for 1 year were alive and recurrence-free, and 92% of the patients receiving imatinib for 3 years were alive, compared with 82% of patients assigned to 1 year of therapy. Only 4% of patients developed recurrence of GIST during treatment with imatinib. However, significant side effects from adjuvant imatinib may occur, and approximately 25% of patients assigned to imatinib for 3 years discontinued treatment early for reasons other than tumor recurrence.

Suggested Reading

Joensuu H, Eriksson M, Sundby Hall K, et al. One vs three years of adjuvant imatinib for operable gastrointestinal stromal tumor: a randomized trial. JAMA. 2012;307:1265-1272. PMID: 22453568.

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