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In Reply

Geneva Cancer Registry, Institute for Social and Preventive Medicine, University of Geneva, Geneva, Switzerland

We appreciate the interest of Drs Choi and Robins in our study. ¹ They argue that the survival benefit of surgery of the primary tumor does not derive from prevention of new metastases because the survival curves diverged from the beginning. Such a conclusion, however, can not be drawn from curves predicted from a multiadjusted Cox model. The Cox model assumes that the ratio of hazard functions is constant over time and at any time of the study the two hazard functions are proportional to one other. Therefore, they are simply not suitable for conclusions on timing of diverging.

We agree with the authors, however, that the reason for better survival of patients who could undergo complete resection of the primary tumor is far from being understood. We also agree, and in the article we acknowledged it, that even after all our efforts to reduce the selection bias due to unrecorded factors, a residual confounding is still likely. For these reasons we conclude that only a clinical trial will be able to test our hypothesis.

AUTHORS' DISCLOSURES OF POTENTIAL CONFLICTS OF INTEREST

The authors indicated no potential conflicts of interest.

ACKNOWLEDGMENTS

Supported in part by PROSPER Grant No. 323-3069350 from the Swiss National Science Foundation (H.M.V.).

REFERENCES

1. Rapiti E, Verkooijen HM, Vlastos G, et al: Complete excision of primary breast tumor improves survival of patients with metastatic breast cancer at diagnosis. J Clin Oncol 24:2743-2749, 2006[Abstract/Free Full Text]

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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 Rapiti, E. Articles by Bouchardy, C. Search for Related Content PubMed Articles by Rapiti, E. Articles by Bouchardy, C. Social Bookmarking                            What's this?