Dutasteride Reduces Prostate Cancer Risk in High-Risk Men

In men deemed at high risk for developing prostate cancer, the dual 5α-reductase inhibitor dutasteride (Avodart) reduced the risk of biopsy-detectable prostate cancer across multiple subgroups by 16% to 32%, according to a subgroup analysis of the REDUCE trial (Reduction by DUtasteride of prostate Cancer Events) presented at the ECCO 15 - ESMO 34 Joint Congress. The results confirm the utility of dual 5α-reductase inhibition in reducing cancer risk, said Michael Marberger, MD, of the University of Vienna, Austria, who presented the results.

“There was a significant reduction in risk of prostate cancer with dutasteride versus placebo, regardless of the baseline variable evaluated, which included age, family history, International Prostate Symptom Score (IPSS), number of cores in the baseline biopsy, prostate volume, prostate-specific antigen (PSA) levels, percent free PSA, and body mass index,” Dr Marberger announced. The findings are consistent with the overall 23% relative risk reduction found for dutasteride versus placebo in the general study population (P < .0001), as noted in a study presented at the American Urology Association annual 2009 meeting, he added.

REDUCE included 8121 subjects with PSA levels of 2.5 to 10.0 ng/mL (age, 50-60 years) or 3.0 to 10.0 ng/mL (age >60 years), plus a negative prostate biopsy within 6 months prior to study entry, which was 83% of the general efficacy population. The study-mandated that 10-core biopsies be taken after 2 and 4 year but that for-cause biopsies could be performed at any time. The current analysis examined risk reduction according to subjects’ baseline characteristics and found that dutasteride reduced the rate of prostate cancer across various patient segments, including:

• 22.1% in men ≥ 65 years of age

• 25.9% in men with baseline IPSS ≥ 8

• 16.0% in men with baseline prostate volume of 36.6 mL to <51.8 mL

• 32.1% in men with prostate volume of ≥ 51.8 mL

• 23.4% in men with baseline PSA of 4.9 to <6.8 ng/mL

• 23.1% in men with baseline PSA of ≥ 6.8 ng/mL

• 25.4% in men with baseline percent free PSA ≥ 18.6 ng/mL

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• 24.1% in men with baseline BMP of 25.5 to < 28.4 kg/m

In all pre-specified baseline subgroups, risk reduction was observed, emphasized Dr Marberger, and noted that “the data are clear” that risk can be reduced by at least 23% with this agent, and he advocated the use (off label) of dutasteride for cancer prevention in certain populations. The typical candidate might be a patient at higher risk due to elevated PSA levels and large prostate volume and is “very motivated” to prevent this disease, as they would have to accept the potential for side effects, including reduced sexual function and reduced ejaculate volume.

ECCO/ESMO Abstract O-7006