Regarding the article below... How does this reversal affect the PCa?

Reuters Health, By David Douglas, Wednesday, March 23, 2005

NEW YORK (Reuters Health) - Men with more advanced prostate cancer
often undergo treatment to reduce levels of testosterone, which drives
tumor growth. Now, a new study shows that this so-called androgen
deprivation can be rapidly reversed.

In the study, testosterone levels that were effectively supressed with
a hydrogel implant releasing the hormone-suppressing drug histrelin
rebounded rapidly after removal of the implant. However, the rebound
was not as swift when a similar therapy called depot GnRH was injected,
Israeli researchers report.

To examine the reversibility of androgen deprivation, Dr. Alon Fridmans
of Shaare Zedek Medical Center, Jerusalem, and colleagues studied 22
men with prostate cancer.

Of these, seven had been treated via a hydrogel implant containing
histrelin for up to 3 years, eight had been treated with long-term
depot GnRH super agonists and the remaining seven, who had had no prior
hormonal therapy, received the testosterone-suppressing drug
bicalutamide.

In the implant group, levels of both testosterone and luteinizing
hormone (LH), which drives up testosterone levels, were reduced to the
castration range. When the implant was removed, LH increased within 6
weeks and testosterone also increased.

However, patients in the depot group showed suppression of
testosterone, LH and prostate specific antigen for at least 9 months
after their last injection.

In six of the seven hormonal therapy-naive patients, there was a
significant increase in testosterone and LH within 7 days of starting
bicalutamide.

The researchers thus point out that histrelin implants allow simple
implementation of intermittent hormonal therapy.

However, because of the long-term effects of depot injection, they
conclude that serum testosterone must return to normal levels before
depot injection interruption can be construed as "bona fide
intermittent therapy."

Moreover, Fridmans told Reuters Health because of these lasting
effects, it also "may be possible to space GnRH analog administration
at longer time intervals rather than the 2-3 monthly intervals
currently recommended." The study findings appear in the March issue of
the Journal of Urology.

SOURCE: Journal of Urology March, 2005.