Refers to article:
Impact of 5-Alpha Reductase Inhibitors on Men Followed by Active Surveillance for Prostate Cancer: A Time-dependent Covariate Reanalysis
Accepted 10 April 2013
August 2013 (Vol. 64, Issue 2, page 343)
I am happy to see that this team has used a time-dependent covariate analysis in reevaluating their observational study on the effect of 5α-reductase inhibitors (5-ARIs) on pathologic progression in men on active surveillance . Although their reanalysis supports their original conclusions, the findings are still quite different from the results of the randomized trial on the subject .
In the REDEEM study, at 18 mo there was only a slight decrease in pathologic progression in men receiving dutasteride compared to the control group (23% vs 35%), and at 36 mo there was no effect . In contrast, Finelli et al. found that the effect of 5-ARIs persisted and increased with time . Thus there must be some other factor that needs to be considered. I suggest that it may be ascertainment bias.
Patients underwent protocol biopsies at specific times in the REDEEM study (18 mo and 36 mo)  and every year in the study by Ross et al. . In contrast, in addition to protocol biopsies (12 mo and then every 2–3 yr) in the study by Finelli et al. , biopsies were also performed earlier if prostate-specific antigen (PSA) velocity was rapid or at the discretion of the caring physician. In this nonrandomized retrospective nonblinded study, it is easy to imagine that both patients and physicians could be lulled into a false sense of security by low levels of PSA and PSA velocity in patients taking finasteride. Thus reluctance to perform a biopsy may explain the results. This confounding factor limits the ability of the authors to conclude that 5-ARIs provide a protective effect in this setting.
Conflicts of interest
The author has nothing to disclose.
-  L.-M. Wong, N. Fleshner, A. Finelli. Impact of 5-alpha reductase inhibitors on men followed by active surveillance for prostate cancer: a time-dependent covariate reanalysis. Eur Urol. 2013;64:343 Crossref
-  A. Finelli, G. Trottier, N. Lawrentschuk, et al. Impact of 5-α-reductase inhibitors on men followed by active surveillance for prostate cancer. Eur Urol. 2011;59:509-514 Crossref
-  A.E. Ross, Z. Feng, P.M. Pierorazio, et al. Effect of treatment with 5-α reductase inhibitors on progression in monitored men with favourable-risk prostate cancer. BJU Int. 2012;110:651-657 Crossref
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© 2013 European Association of Urology, Published by Elsevier B.V.