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. 1997;76(4):551–558. doi: 10.1038/bjc.1997.424

Cautionary tales of survival analysis: conflicting analyses from a clinical trial in breast cancer.

W M Gregory 1, K Bolland 1, J Whitehead 1, R L Souhami 1
PMCID: PMC2227982  PMID: 9275036

Abstract

Data from a completed randomized trial in breast cancer are used to demonstrate and quantify the variation in estimated survival curves and log-rank statistics at different times throughout a trial. False 'plateaux' are common, as are wide fluctuations in chi2 values obtained from the log-rank test when there are few events. We show how analyses conducted at different times can demonstrate different effects. Long follow-up is often necessary to allow correct interpretation of results. We discuss the assumption of proportional hazards and the consequences of making that assumption inappropriately. We show how checking whether hazards are proportional can help in avoiding erroneous conclusions.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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