Modeling and analysis of gleason score 8-10 prostate cancers in the REDUCE study

Gerald L. Andriole, David G. Bostwick, Leonard G. Gomella, Michael Marberger, Francesco Montorsi, Teuvo L. Tammela, Donald J. Tindall, Ivy L. Fowler, Harmony P. Garges, Timothy H. Wilson, Ramiro Castro

Research output: Contribution to journalArticle

5 Scopus citations

Abstract

Objective To explore explanations for the numerical imbalance of biopsy-detected Gleason 8-10 prostate cancers (PCa) diagnosed in years 3-4 in the dutasteride and placebo groups of the Reduction by Dutasteride of Prostate Cancer Events (REDUCE) study. Methods REDUCE was a 4-year, randomized, double-blind, placebo-controlled trial of dutasteride (0.5 mg/d) vs placebo for PCa risk reduction. We modeled the incidence of Gleason 8-10 cancer and used logistic regression analysis to evaluate the effects of baseline predictors of PCa, as well as post-baseline prostate volume at the time of biopsy, on PCa diagnosis. We compared needle biopsy Gleason scores with corresponding surgery Gleason scores. All statistical tests conducted were 2-sided. Results Had there been a scheduled biopsy occurring only at year 4, we estimated a similar incidence of Gleason 8-10 PCa in the dutasteride (n = 45) and placebo (n = 46) groups. Two biopsy Gleason 7 cancers in the placebo group (n = 150) were upgraded to Gleason 8-10 cancer on prostatectomy, and no patients in the dutasteride group (n = 111) were upgraded. Logistic regression analysis demonstrated the effect of prostate volume on Gleason 8-10 cancer diagnosis. Conclusion Although modeling of REDUCE data showed a similar incidence of Gleason 8-10 cancer in the dutasteride and placebo groups at year 4, an association between dutasteride and Gleason 8-10 cancer cannot be definitely excluded. It is likely that several biases, notably study design and prostate size at the time of biopsy, contributed to the numerical imbalance in Gleason 8-10 cancers observed between the treatment groups in years 3-4.

Original languageEnglish (US)
Pages (from-to)393-399
Number of pages7
JournalUrology
Volume84
Issue number2
DOIs
StatePublished - Aug 2014

ASJC Scopus subject areas

  • Urology

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    Andriole, G. L., Bostwick, D. G., Gomella, L. G., Marberger, M., Montorsi, F., Tammela, T. L., Tindall, D. J., Fowler, I. L., Garges, H. P., Wilson, T. H., & Castro, R. (2014). Modeling and analysis of gleason score 8-10 prostate cancers in the REDUCE study. Urology, 84(2), 393-399. https://doi.org/10.1016/j.urology.2014.04.016