Tuesday’s news and reports: December 16, 2008

There are a number of interesting (if somewhat technical) reports today dealing with the following issues:

  • The size and metabolism of the “normal” prostate and their relationship to age
  • Defining who is potentially appropriate for focal therapy
  • Saw palmetto berry extract as an anti-tumor agent?
  • Is chlormanidone a helpful non-steroidal antiandrogen?

Jadvar et al. have examined data from PET-CT scans of 154 normal men, ranging from 22 to 97 years of age , who had no prior evidence of prostate cancer, to investiagte the effects of aging on prostate metabolism and prostate size. According to their data, while the normal prostate increases in size with age, this increase in size does not significantly affect the gland’s metabolism or its density when viewed under PET-CT. This leads one to ask again whether age-related PSA cut-off levels are, in fact, appropriate in any way as screening parameters for prostate cancer. Ever since the completion of the Prostate Cancer Prevention Trial, many urologists have been arguing that there is no such thing as a “safe” PSA level, below which a man’s risk for prostate cancer is effectively zero.

Tareen et al. have published data suggesting that the numbers of men in contemporary cohorts who are actually potentially appropriate candidates for so-called “focal” or “hemiablative focal” therapy may be small. Based on a review of records of 1,467 consecutive men who underwent open RP by a single surgeon from January 2000 to June 2007, they were only able to identify a total of 163 men (11.1 percent) who had unilateral, low-risk disease (defined as a PSA level < 10 ng/ml, a Gleason score < 7, and a percentage tumor involvement of < 10 percent). Tareen and colleagues suggest that before proceeding with focal therapy, the urology community needs to clearly identify accurate, prospective methods for candidate selection.

The use of saw palmetto extracts has long been common in the management of prostate disorders (mostly for benign prostatic hyperplasia or enlargement of the prostate, which is common with increasing age). Now Scholtysek et al. have reported that one form of saw palmetto berry extract, as well as two of its sterol components (β-sitosterol and stigmasterol), have potential as anti-tumor agents. This is pre-clinical research “in vitro,” and so we shouldn’t read too much into this report without additional supporting evidence, but some will feel that this report justifies their long-term confidence in saw palmetto, which has certainly been used over the years to lower PSA levels in some patients.

Sakai et al. are reporting that (at least in Japanese men receiving combined androgen deprivation) there may be a lower incidence of hot flashes among men treated with leuprolide acetate + the steroidal antiandrogen chlormadinone than with leuprolide acetate + the non-steroidal antiandrogen bicalutamide. However, this was a relatively small study with only 124 evaluable patients, and the devil is in the details. According to the authors, “Although the incidence of hot flashes … tended to be greater in the bicalutamide group than in the chlormadinone group, no significant difference was noted in the cumulative incidence of hot flashes at 2 years.” Chlormanidone acetate is an active synthetic progestational hormone used in drug combinations as an oral contraceptive. We are aware of no other data on the use of this agent in the treatment of advanced prostate cancer, and we would not expect to see further use of this drug in prostate cancer without a great deal more evidence of its safety and effectiveness.

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