UroToday - Does the Level of Prostate Cancer Risk Affect Cancer Prevention with Finasteride? - Abstract

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Wednesday, 14 May 2008

Department of Urology, University of Texas Health Science Center at San

, San , Texas 78229, USA.

thompsoni@...

Finasteride reduced the risk of prostate cancer by 24.8% in the Prostate

Cancer Prevention Trial (PCPT). Whether this represents treatment or

prevention and who is most likely to benefit are unknown. We sought to

clarify these issues by this investigation.

We fit a logistic regression model to men in the placebo group of the PCPT

using risk factors for prostate cancer at entry to predict prostate cancer

during the subsequent 7 years of study. Men in the two treatment groups were

categorized into quintiles of risk of prostate cancer based on the

predictive logistic model. A second model was fit evaluating finasteride's

effect on prostate cancer for each subgroup defined by quartiles of baseline

prostate-specific antigen (PSA) . The magnitude of the prevention effect of

finasteride on prostate cancer was then evaluated across risk and PSA

strata.

Finasteride significantly reduced prostate cancer risk for all risk

quintiles. For quintiles 1 through 5, odds ratios were 0.72, 0.52, 0.64,

0.66, and 0.71, respectively (all P < or = 0.05). For quartiles of risk of

entry PSA (less than 0.7 ng/mL, 0.7 to 1.1 ng/mL, 1.1 to 1.7 ng/mL, and 1.8

to 3.0 ng/mL), odds ratios increased (smaller treatment effect) as PSA

increased: 0.60, 0.62, 0.66, and 0.69, respectively, but remained

significant for all strata (each P < 0.001).

Finasteride significantly reduced prostate cancer risk regardless of the

level of this risk, estimated either by multivariable risk or by PSA

stratum; this suggests that finasteride exerts both treatment and preventive

effects. All men undergoing PSA screening should be informed of the

potential for finasteride to reduce their risk of prostate cancer.

Written by

IM, Tangen CM, Parnes HL, Lippman SM, Coltman CA Jr.

Reference

Urology. 2008 May;71(5):854-7.

PubMed Abstract

PMID:18455628