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In Reply

Emma Children’s Hospital AMC, Pediatric Surgical Center of Amsterdam, Amsterdam, the Netherlands

Meyers et al criticize the methodology with which the value of the Pretreatment Extent of Disease (PRETEXT) system has been evaluated, and question the validity of the comparison between PRETEXT and the Children's Cancer Study Group/Pediatric Oncology Group (CCSG/POG) staging. Because we compared PRETEXT with a gold standard (which is essential for a good epidemiologic study),¹ the study had to be limited to the comparison of the preoperative PRETEXT with the (postoperative) resection specimen. This indeed had the consequence that only patients who had been operated could be included in this comparison. Now that this analysis has shown that PRETEXT staging is accurate and reliable we can move forward, and enthusiastically agree with a widespread start of the use of the PRETEXT system, and to evaluate this system as a risk stratification tool, in order to be able "to let the numbers speak."

We do agree with Meyers et al that the retrospective application of the CCSG/POG staging system to our SIOPEL-1 data set is not a valid application of this staging system as such, which has been clearly stated on page 1247: "We are aware that ... the CCSG/POG staging system and TNM staging system are postoperative staging systems that are validated on the surgical results before any other therapeutic intervention, and that now are being applied to patients who have been pretreated with chemotherapy."¹ For the sake of clarity, from then on we therefore spoke about the CCSG/POG-based staging system and TNM-based staging system, respectively, in order to make this difference with the original staging systems transparent. In the Discussion, the lesser predictive value of the CCSG/POG-based system we found, was explained by the "select group of patients."¹ We are therefore grateful with their comments that the true CCSG/POG staging system has been designed and validated as a postoperative staging system, and should not be applied otherwise in patient care.

We would like to stress that the aim of this article was to analyze and validate the properties of the PRETEXT staging system, and to show its accuracy, reproducibility, and predictive value. Based on these properties we advocate the use of PRETEXT for all groups treating hepatoblastoma patients (be it as an extra staging next to the use of their own preferred staging system) as a tool to make the comparison of treatment results more accurate.

AUTHOR'S DISCLOSURES OF POTENTIAL CONFLICTS OF INTEREST

The author indicated no potential conflicts of interest.

REFERENCES

1. Aronson DC, Schnater JM, Staalman CR, et al: Predictive value of the pretreatment extent of disease system in hepatoblastoma: Results from the International Society of Pediatric Oncology Liver Tumor study group SIOPEL-1 study. J Clin Oncol 23:1245-1252, 2005[Abstract/Free Full Text]

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Related Correspondence

• Predictive Value of Staging Systems in Hepatoblastoma
  Rebecka L. Meyers, Howard M. Katzenstein, and Marcio H. Malogolowkin
  JCO 2007 25: 737 [Full Text]

This Article Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Alert me to new issues of the journal Save to my personal folders Download to citation manager Rights & Permissions Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Aronson, D. C. Search for Related Content PubMed Articles by Aronson, D. C. Related Articles Related Correspondence Social Bookmarking                            What's this?