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Originally published as JCO Early Release 10.1200/JCO.2008.19.7673 on November 3 2008 © 2008 American Society of Clinical Oncology.
In Reply
Department of Hematology, Hospices Civils de Lyon and University Claude Bernard, Lyon, France
Division of Hematology/Oncology, Connecticut Children's Medical Center, Hartford, CT
Department of Oncology, St Jude Children's Research Hospital, Memphis, TN
The University of Texas M. D. Anderson Cancer Center, Houston, TX
Division of Pediatric Hematology and Blood and Marrow Transplantation, Columbia University, New York, NY We appreciate the comments by Feusner et al regarding our recent article in Journal of Clinical Oncology.1 We generally agree that there is a paucity of high-level and high-grade published studies on the subject of tumor lysis syndrome (TLS). We also strongly agree that additional well-designed and controlled studies are needed to define risk and determine optimal management of TLS in both children and adults. This article was specifically developed to provide guidelines only, and more importantly, to stimulate future investigations to answer the questions concerning areas in which existing evidence is at a low level or grade. With regard to the specific questions, comments, and recommendations, we offer the following responses. Of course not all patients with Burkitt's lymphoma are considered high risk. There are other risk factors a physician must take into consideration, such as stage, bulk, tumor burden, renal function, and so on, as outlined in Table 4 of the original article. Additionally, we do not recommend that all patients with Burkitt's lymphoma be immediately admitted to an intensive care unit. We recommend that should TLS complications develop, especially severe electrolyte abnormalities, high-risk patients should be in a position to be readily transferred to an intensive care unit. Additional responses to your comments and recommendations are noted in the following paragraphs. First, we appreciate the opportunity to further elaborate on the issue of alkalinization, which was a controversial issue even before the availability of rasburicase. This is because although alkalinization can treat or prevent hyperuricemia, it makes hyperphosphatemia, another component of TLS, worse. Alkalinization hinders the excretion of phosphorus, and may even result in calcium-phosphate precipitation in the renal tubules. With the availability of rasburicase, hyperuricemia is no longer a major problem in patients with TLS. Because alkalinization is not necessary for the prevention of treatment of severe hyperuricemia, the use of rasburicase can actually facilitate the management of hyperphosphatemia. In our phase I/II and randomized trials of rasburicase,2,3 alkalinization was not used in most patients. In these studies, patients did not have a problem with hyperphosphatemia, and in fact, serum phosphorus levels were significantly lower in patients treated with rasburicase than in patients treated with allopurinol. Since rasburicase became available, we have not used alkalinization for the prevention and treatment of TLS. Our decision is certainly based not on animal studies alone but rather on our collective vast clinical experience. Second, in Figure 2 of the treatment algorithm for the prevention and management of hyperuricemia, clinical judgment and monitoring are reserved for low-risk patients. We indicated that adequate hydration and urine output are of high importance in preventing TLS in all patients, and for patients unlikely to develop TLS, it is our opinion that a watch-and-wait approach with close monitoring is entirely appropriate. We could not find the recommendation that Feusner et al claim we have made in the figure or in the text. Nonetheless, we do believe that adequate hydration to maintain good urine output and monitoring are sufficient for the management of patients at low risk. We do not understand the rationale of testing nonalkaline diuresis in low-risk patients proposed by Feusner et al, and seriously doubt that any group will perform such a clinical trial. Third, we certainly agree that the use of one fourth normal saline (a hypotonic solution) in large volumes is hazardous. Again, we believe that Feusner et al may have misunderstood our recommendation. We recommend the use of a solution consisting of one fourth normal saline and 5% dextrose. Fourth, the point on the activity in blood samples before processing is well known and addressed in all published studies with measurement of the effect of rasburicase on uric acid levels.4 The fast drop in uric acid levels presented in all studies corresponds to a true in vivo activity. This point is well described in the summary of product characteristics associated with US Food and Drug Administration and European Medicines Agency files.5 AUTHORS' DISCLOSURES OF POTENTIAL CONFLICTS OF INTEREST Although all authors completed the disclosure declaration, the following author(s) indicated a financial or other interest that is relevant to the subject matter under consideration in this article. Certain relationships marked with a "U" are those for which no compensation was received; those relationships marked with a "C" were compensated. For a detailed description of the disclosure categories, or for more information about ASCO's conflict of interest policy, please refer to the Author Disclosure Declaration and the Disclosures of Potential Conflicts of Interest section in Information for Contributors. Employment or Leadership Position: None Consultant or Advisory Role: Bertrand Coiffier, Sanofi-aventis (C); Mitchell S. Cairo, Sanofi-aventis (C) Stock Ownership: None Honoraria: Bertrand Coiffier, Sanofi-aventis; Ching-Hon Pui, Sanofi-aventis; Anas Younes, Sanofi-aventis; Mitchell S. Cairo, Sanofi-aventis Research Funding: None Expert Testimony: None Other Remuneration: Arnold Altman, Sanofi-aventis NOTES published online ahead of print at www.jco.org on November 3, 2008 REFERENCES
1. Coiffier B, Altman A, Pui CH, et al: Guidelines for the management of pediatric and adult tumor lysis syndrome: An evidence-based review. J Clin Oncol 26:2767-2778, 2008 2. Goldman SC, Holcenberg JS, Finklestein JZ, et al: A randomized comparison between rasburicase and allopurinol in children with lymphoma or leukemia at high risk for tumor lysis. Blood 97:2998-3003, 2001 3. Pui CH, Mahmoud HH, Wiley JM, et al: Recombinant urate oxidase for the prophylaxis or treatment of hyperuricemia in patients with leukemia or lymphoma. J Clin Oncol 19:697-704, 2001 4. Sanofi-aventis: Elitek prescribing information. http://products.sanofi-aventis.us/elitek/elitek.html 5. European Medicines Agency: Annex I: Summary of product characteristics. http://www.emea.europa.eu/humandocs/PDFs/EPAR/fasturtec/437900en1.pdf(EMEA/H/C.331)
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Copyright © 2008 by the American Society of Clinical Oncology, Online ISSN: 1527-7755. Print ISSN: 0732-183X
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