Board Preparation: Gastrointestinal Cancers, Epidemiology & Prevention

Oct 27, 2014

Every issue of ASCO Connection: Trainee & Early-Career Oncologists has an opportunity for you to test your knowledge in order to assist your preparations for Board examinations. Questions come from ASCO-SEP, 3rd edition, ASCO's self-evaluation program, and will cover a variety of cancer types and topics. This issue features the most frequently missed questions from two popular chapters: Gastrointestinal Cancers and Epidemiology & Prevention.

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

1: A 55-year-old man has multiple lung and liver metastases found on routine follow-up computed tomography scan 2 years after treatment for stage III cancer of the sigmoid colon. At that time he was treated with resection of the primary tumor and postoperative adjuvant chemotherapy with 5-fluorouracil (5-FU)/leucovorin.

Examination of a biopsy sample of the liver lesion now demonstrates adenocarcinoma consistent with a primary cancer of the colon. The results of laboratory tests are as follows: total bilirubin, 2.5 mg/dL; direct bilirubin, 0.3 mg/dL; creatinine, 0.8 mg/dL; alkaline phosphatase, 108 U/L; aspartate aminotransferase, 22 U/L; alanine aminotransferase, 12 U/L; and albumin, 4.0 g/dL. The KRAS mutation status of the cancer is unknown.

The patient has a very good performance status, is eager to begin treatment, and understands that no treatment offers curative potential. Which of the following would you recommend?

A. 5-FU/leucovorin/oxaliplatin (FOLFOX) plus bevacizumab

B. 5-FU/leucovorin/irinotecan (FOLFIRI) plus bevacizumab

C. Capecitabine/oxaliplatin (XELOX)

D. FOLFOX plus cetuximab

E. No therapy unless symptoms develop


2: A 69-year-old man has recently completed treatment for early-stage squamous cell carcinoma of the mouth with no evidence of residual disease. However, he continues to smoke two packs of cigarettes daily and is reluctant to quit smoking. To reduce his risk of developing a second cancer and/or of death, he now takes vitamin E and beta-carotene supplements.

Based on the best available clinical trial evidence, you should advise him to:

A. Add selenium supplements

B. Continue with vitamin E supplements

C. Continue with the beta-carotene supplements

D. Discontinue the beta-carotene supplements




1: A

Systemic chemotherapy in advanced colorectal cancer has shown significant improvements in overall survival and quality of life compared with best supportive care. All listed chemotherapy options could represent reasonable choices as first-line therapy. Because the addition of bevacizumab to 5-FU–based first-line chemotherapy has been associated with improved outcome—in particular, prolonged overall survival—a bevacizumab-containing approach would be preferable. In this patient with elevated bilirubin, further aspects must be considered. Patients with abnormal end-organ function (abnormal renal or hepatic function) may have different side effects from irinotecan, capecitabine, or oxaliplatin. The elevated bilirubin could be because of the presence of metastatic disease or Gilbert syndrome. Irinotecan should not be given to patients with Gilbert syndrome and/or elevated bilirubin without significant dose reductions. Cetuximab should only be used when KRAS wild-type status of the cancer has been confirmed. Thus, FOLFOX plus bevacizumab appears to be the best alternative in this scenario.

Suggested Reading

Innocenti F, Ratain MJ. Irinotecan treatment in cancer patients with UGT1A1 polymorphisms. Oncology. 2003;17:52-55. PMID: 12800608.

Cunningham D, Humblet Y, Siena S, et al. Cetuximab monotherapy and cetuximab plus irinotecan in irinotecan-refractory metastatic colorectal cancer. N Engl J Med. 2004;351:337-345. PMID: 15269313.

Goldberg RM, Sargent DJ, Morton RF, et al. A randomized controlled trial of fluorouracil plus leucovorin, irinotecan, and oxaliplatin combinations in patients with previously untreated metastatic colorectal cancer. J Clin Oncol. 2004;22:23-30. PMID: 14665611.

Hurwitz H, Fehrenbacher L, Novotny W, et al. Bevacizumab plus irinotecan, fluorouracil, and leucovorin for metastatic colorectal cancer. N Engl J Med. 2004;350:2335-2342. PMID: 15175435.


2: D

Although there is preliminary evidence that selenium may hold value for cancer prevention, the data are not definitive. Although vitamin E has been suggested to have some value in preventing prostate cancer in smokers, it has not proven effective in preventing head and neck cancers. In smokers, the data are quite compelling that supplemental beta-carotene can increase the risk of lung cancer. This has been seen in trials of high-risk populations, including patients who have previously had mouth and throat cancers.

Suggested Reading

The Alpha-Tocopherol, Beta Carotene Cancer Prevention Study Group. The effect of vitamin E and beta carotene on the incidence of lung cancer and other cancers in male smokers. N Engl J Med. 1994;330:1029-1035. PMID: 8127329.

Heinonen OP, Albanes D, Virtamo J, et al. Prostate cancer and supplementation with alpha-tocopherol and beta-carotene: Incidence and mortality in a controlled trial. J Natl Cancer Inst. 1998;90:440-446. PMID: 9521168.

Mayne ST, Cartmel B, Baum M, et al. Randomized trial of supplemental beta-carotene to prevent second head and neck cancer. Cancer Res. 2001;61:1457-1463. PMID: 11245451.

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