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Journal of Clinical Oncology, Vol 25, No 10 (April 1), 2007: pp. 1293-a-1294 © 2007 American Society of Clinical Oncology. DOI: 10.1200/JCO.2006.10.0974
Carcinoembryonic Antigen Monitoring for Early Detection of Asymptomatic Incurable Metastatic Colorectal CancerDepartment of Medical Oncology, Carlo Fidani Peel Regional Cancer Center, Mississauga, Ontario, Canada To the Editor: In the American Society of Clinical Oncology 2006 update of recommendations for the use of gastrointestinal tumor markers, a major change from the previous guideline is that carcinoembryonic antigen (CEA) should now be utilized for early detection of asymptomatic incurable metastatic disease with the belief that immediate intervention with chemotherapy will result in improved survival.1 However, clinical trial data does not support this notion. In asymptomatic patients with stage IV colon cancer, chemotherapy can be given on diagnosis or on an expectancy basis for symptomatic progression. The use of expectant chemotherapy in metastatic colorectal cancer has been the premise of three separate trials. The Nordic study2 that showed a survival advantage for early chemotherapy compared with watchful waiting had major methodologic flaws. Only 57% of patients randomly assigned to expectant chemotherapy ever received treatment. In addition there were major prognostic imbalances favoring the immediate treatment arm and there was no standardization of chemotherapy when it was given in the watchful waiting group. As a result, two additional studies of identical design comparing immediate with delayed chemotherapy have been carried out. These were combined in a preplanned meta-analysis3 with the result that overall survival was the same regardless of the strategy employed. In addition, quality of life analysis indicated no benefit to either approach. Obviously the limitation to these studies is that they were carried out in an era of modulated fluorouracil only treatment. The introduction of additional agents has improved overall survival in colon cancer4,5 and their incorporation in the treatment algorithm in the hopes of optimizing outcome has replaced the debate about the timing of chemotherapy initiation. However, with these new agents come increased toxicity and thus the question of when to start treatment in asymptomatic patients with metastatic colon cancer remains relevant and unanswered. AUTHOR'S DISCLOSURES OF POTENTIAL CONFLICTS OF INTEREST The author indicated no potential conflicts of interest. REFERENCES
1. Locker GY, Hamilton S, Harris J, et al: ASCO 2006 update of recommendations for the use of tumor markers in gastrointestinal cancers. J Clin Oncol 24:5313-5327, 2006 2. Nordic Gastrointestinal Tumor Adjuvant Therapy Group: Expectancy or primary chemotherapy in patients with advanced asymptomatic colon cancer: A randomized trial – Nordic Gastrointestinal Tumor Adjuvant Therapy Group. J Clin Oncol 10:905-911, 1992 3. Ackland SP, Jones M, Du T, et al: A meta-analysis of two randomized trials of early chemotherapy in asymptomatic metastatic colorectal cancer. Br J Cancer 93:1236-1243, 2005[CrossRef][Medline] 4. Goldberg RM, Sargent DJ, Morton RF, et al: A randomized controlled trial of fluorouracil plus leucovorin, irinotecan, oxaliplatin combinations in patients with previously untreated metastatic colorectal cancer. J Clin Oncol 22:23-30, 2004 5. Hurwitz H, Fehrenbacher L, Novotny W, et al: Bevacizumab plus irinotecan, flurouracil and leucovorin for metastatic colorectal cancer. N Engl J Med 350:2335-2342, 2004 Related Reply
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Copyright © 2007 by the American Society of Clinical Oncology, Online ISSN: 1527-7755. Print ISSN: 0732-183X
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