Two New Clinical Trials:

Prevention of Prostate Cancer,
Osteoporosis in Men Under Study
By Toni Baker
Oct. 20, 2004;
edited by J. Strax Oct. 27, 2004

Preventing prostate cancer and helping men in treatment for prostate
cancer to avoid osteoporosis is the focus of two new clinical trials at
the Medical College of Georgia.

Located in Augusta, Georgia, the Medical College is participating in a
national study to find out whether men can reduce their prostate cancer
risk by taking a drug that halts the conversion of testosterone, the
male hormone, to a more potent hormone that stimulates prostate cancer
growth.
The lifetime risk of prostate cancer is about 1 in 6 for American men,
except for blacks as well as men with a family history who are at
increased risk, according to the National Prostate Cancer Coalition; the
risk increases to about 50 percent by age 80.

MCG also is a study site for a national study looking at whether a new
drug that slows bone resorption can help prostate cancer patients avoid
osteoporosis.
The cancer prevention study examines the potential of dutasteride, the
active ingredient in a drug marketed to treat prostate enlargement, a
common problem of aging.
"While there is no direct relationship between prostate enlargement and
prostate cancer, both cancerous and benign growth of the prostate appear
to be stimulated by this super hormone called dihydrotestosterone," says
Dr. James A. Brown, MCG urologist specializing in prostate cancer. For
some unknown reason, circulating male hormone, testosterone, is
converted into this more potent male hormone in the prostate gland and
scalp.
"What is neat about that is if you can prevent that conversion … you
are taking away a potent stimulator of cell growth," says the Georgia
Cancer Coalition Distinguished Cancer Clinician and Scientist. "Many of
the cells in the gland will atrophy and shrink away."
For the prevention study, MCG is evaluating patients age 50-75 with
elevated PSAs, a marker for prostate cancer, who have had a negative
biopsy in the last six months. The study runs for four years and
participants will receive additional biopsies at years two and four.
The osteoporosis prevention study looks at the bone-thinning disease
often associated with menopausal women. Loss of the female hormone,
estrogen, helps disrupt the normal balance between cells called
osteoblasts that make bone and osteoclasts that consume it.
Some details about this trial can be read online under the title Calcium
With or Without Estrogen and/or Risedronate in Preventing Osteoporosis
in Patients with Prostate Cancer.

Another Phase III randomized trial for osteoporisis prevention is
recruiting at Herbert Irving Comprehensive Cancer Center at Columbia
University, New York,  New York,  10032: Zoledronate and Estradiol
in Preventing Bone Loss in Patients With Prostate Cancer
While men also naturally experience a decline in their testosterone
level with age, they keep making the hormone throughout life and tend to
start out with denser bones than women, unless they get prostate cancer
and receive hormonal blockade for the disease.
But prostate cancer, much like breast cancer, is a hormone-dependent
cancer, If surgery, brachytherapy or external beam radiotherapy fail or
if the disease is found too late for curative treatment, a mainstay of
treatment of advanced disease is hormone blockade.

"Testicles make male hormone," says Dr. Brown. "The prostate gland is a
sex organ that responds to male hormone. This gland develops at puberty,
with the influx of hormones, but it will often continue to grow
throughout life, which is why sometimes with age, men have problems with
an enlarged prostate. Prostate cancer also will grow more rapidly and
aggressively with male hormone circulating."

Faced with a need to halt testosterone production, most men today shun
surgical removal of the testicles (orchiectomy) and prefer to take one
or more drugs that suppress hormone production. Intermittent use of
hormonal blockade is becoming more widespread. Even so, these drugs take
a toll on general health including bone density.
"The mainstay of prostate cancer therapy is anti-hormone therapy and men
typically are on it for years," says Dr. Brown. Side effects often
include markedly reduced libido as well as the increased risk of
osteoporosis.

The study looks as a new bisphosphonate, called risedronate, that may
slow bone resorption and may help correct the bone deficit that occurs
with anti-hormone therapy, Dr. Brown says. For this study, MCG is
looking for men with prostate cancer who are taking anti-hormone therapy
for their disease. Participants will be followed for two years; half
will receive the study drug and half will receive placebo. MCG expects
to enroll about 20 patients in the study that will follow 1,200 men
nationally.

A Phase III trial that gives half the patients a placebo (a sugar pill
or fake drug) puts you at risk 50/50 of going without a treatment you
may need. Can you get an already tested, good-enough version of the drug
without entering the trial?

If you already have early signs of weak bones, you may need to start
taking a medication now. Men taking hormonal blockade for prostate
cancer are advised to get a baseline bone density scan and to start
taking preventive medication such as Fosamax, Aredia or Zometa. Test
have shown that hormonal treatment starts to weaken bone in months.

The 2 trials in the box above give patients a chance to take estrogen or
estradiol along with calcium. These types of hormonal therapy may
protect bones. Both these drugs are available on prescription. Some
oncologists already prescribe them for prostate cancer patients in place
of Lupron/Zoladex or after those drugs fail.

For more information about the studies contact Mary Anne Park, director
of the MCG Surgical Research Service, at 706-721-0193 or check the NCI
listings. 

knowledge is power - growing old is mandatory - growing wise is optional    
"Many more men die with prostate cancer than of it. Growing old is
invariably fatal. Prostate cancer is only sometimes so."