Diet, Drugs May Stop Prostate Cancer
Trials Poised to Identify Prevention Strategies
Sept. 24, 2007 -- How to lower cancer risk in men is one of the hottest
areas in prevention research. Now a new study shows there should be some
definitive answers on prostate cancer within the next few years.
A host of trials are under way investigating drug treatments, nutritional
supplements, and foods that have shown promise for the prevention of prostate
Urologist and prostate cancer researcher Neil Fleshner, MD, MPH, of the
University of Toronto, says these trials should soon lead to effective
evidence-based strategies to prevent the disease.
Fleshner’s review of the prostate cancer prevention research appears in the
latest online issue of the journal Cancer.
“There is great hope that within the next five years we will have relatively
inexpensive and very effective ways to minimize the burden of prostate cancer,”
he tells WebMD.
But a cancer epidemiologist who also spoke to WebMD called the five-year
“Results from these clinical trials should shed some light on what can be
done, but I am doubtful that they will provide all the answers,” says Carmen
Rodriguez, MD, of the American Cancer Society.
Food, Drug Strategies for Prevention
Several studies have linked the consumption of animal fat -- especially fat
found in red meat and high-fat dairy products -- to an increase in
prostate cancer risk.
The overall health benefits of limiting red meat and high-fat dairy foods
are well-known. Fleshner says reducing prostate cancer risk may prove to be one
more benefit of eating a diet high in fruits and vegetables and low in animal
One of the most promising strategies for preventing prostate cancer in
high-risk men had been treatment with the prostate enlargement drug finasteride
(known commercially as Proscar) or similar drugs.
But a large trial of finasteride, involving close to 19,000 men who were at
average risk for developing the disease, produced confusing results.
While the men in the Prostate Cancer Prevention Trial (PCPT) who took the
drug had a 25% reduction in prostate cancers compared with men who didn't, they
also had more advanced and aggressive tumors.
The clinical significance of both of these findings remains in doubt. It is
not clear if finasteride actually promotes higher-grade tumors or if the
finding was due to the study design.
But the bigger reason why the drug is not used more for prostate cancer
prevention is doubt about whether it prevents cancers that lead to death,
“Most doctors still have questions about whether the types of tumors
prevented with finasteride are actually clinically relevant,” he says.
It is also not clear if potential side effects, such as impotence and
decreased sex drive, will keep men from taking the drug for prostate cancer
prevention or just who should take it if it proves beneficial, Rodriguez
A large clinical trial of a similar drug, Avodart, is ongoing. The trial
involves more than 8,000 men at high risk for developing prostate cancer, and
results are expected within the next few years.
Another approach to chemoprevention involves treatment with the antiestrogen
breast cancer drug Fareston.
Early trials found that men treated with low doses of the drug (20
milligrams) developed slightly fewer prostate cancers than those treated with
placebo or higher doses of Fareston. Results from a definitive study should be
reported within the next two years, Fleshner says.