Re: Proscar as a cancer preventive

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> New York
>
> The American Cancer Society and the National Cancer Institute have hailed
> the trial of a drug for prostate cancer as a milestone for cancer
> prevention, although the treatment can increase the aggressiveness of the
> cancer in some cases. And some commentators have questioned its use as a
> preventive, given the trial results.
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> Finasteride (Proscar), which is manufactured by Merck, reduced the

> of prostate cancer by nearly 25% in a large, randomised, controlled trial
> and reduced symptoms of benign prostatic hypertrophy.
>
> But prostate cancers that developed during the course of the trial were

> aggressive in the treatment group than in the placebo group, says the

> which is released early online by the New England Journal of Medicine
> (www.nejm.org) and will be published in the 17 July issue. The study also
> showed that, in the control group, the number of cancers detected was four
> times higher than expected.
>
> These two factors, says Dr Peter Scardino, head of urology at Memorial
> Sloan-Kettering Cancer Center, New York, in an accompanying editorial,

> serious concern about the clinical significance of the cancers detected

> the reduction achieved with the treatment. He said that "disturbing

> in the report argue that it [finasteride] should not" be used to lower the
> risk of prostate cancer.
>
> Finasteride lowers concentrations of androgens, which are involved in the
> development of prostate cancer. Androgen deprivation is one treatment for
> prostate cancer. Finasteride inhibits 5-reductase, reducing conversion of
> testosterone to dihydrotestosterone, the main androgen in the prostate.
>
> The study enrolled 18 882 men aged 55 years or more whose results of

> rectal examination were normal and who had a prostate specific antigen
> concentration of 3.0 ng/ml. The men were to be followed for seven years,

> the study ended early when it was found that finasteride reduced the
> incidence of prostate cancer in 9060 men by 24.8% (95% confidence interval
> 18.6% to 30.6%; P<0.001).
>
> Although men who took finasteride had fewer prostate cancers, men who did
> develop prostate cancer while taking finasteride were more likely to have
> aggressive cancer-defined as a Gleason score of 7 to 10-than the men in

> placebo group (P for difference <0.001). However, the Gleason score is

> on a pathologist's visual inspection of prostate cancer cells, and
> finasteride affects the appearance of the cells, perhaps leading to a

> estimate of the score. Or the drug might have eliminated less serious
> cancers, while allowing more serious ones to grow.
>
> Finasteride reduced the risk of prostate cancer in all risk groups. It

> reduced urinary tract symptoms of benign prostatic hypertrophy. However,

> taking finasteride had more sexual side effects.
>
> The study protocol called for a biopsy in all men who hadn't had a

> of prostate cancer by the end of the study. This meant that men who would
> not normally have had a biopsy did have one. The surprising finding was

> high risk cancers (according to the Gleason score) were as common in men
> with very low prostate specific antigen concentrations as in men with high
> concentrations.
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