J Urol. 2009 Nov;182(5):2265-72. Epub 2009 Sep 16.
Lack of an effect of high dose isoflavones in men with prostate cancer undergoing androgen deprivation therapy.
Sharma P, Wisniewski A, Braga-Basaria M, Xu X, Yep M, Denmeade S, Dobs AS, DeWeese T, Carducci M, Basaria S.
Georgetown University, Washington, DC, USA.
The profound hypogonadism due to androgen deprivation therapy for
prostate cancer results in complications such as sexual dysfunction,
poor quality of life, vasomotor symptoms and altered cognition. Since
estrogen is associated with cardiovascular risks, phytoestrogens are
being increasingly evaluated as a potential treatment for these adverse
effects. We evaluated the effects of high dose isoflavones, equivalent
to that consumed by Asian populations, on the aforementioned
consequences of androgen deprivation therapy.
MATERIALS AND METHODS: A
total of 33 men undergoing androgen deprivation therapy for prostate
cancer were enrolled in this randomized, double-blind, placebo
controlled, 12-week pilot trial. Participants were randomly assigned to
receive 20 gm soy protein containing 160 mg total isoflavones (17) vs
taste matched placebo, that is 20 gm whole milk protein (16). The study
was performed at a tertiary care center in the United States.
At baseline the groups were well matched in demographic parameters,
sleep quality, cognition and overall quality of life. However, men in
the isoflavone group had a higher baseline prevalence of hot flashes
and poor intercourse satisfaction compared to those on placebo. At 12
weeks there were no significant differences between the 2 groups in any
CONCLUSIONS: This pilot study of high dose isoflavones
in androgen deprived men showed no significant improvement in
cognition, vasomotor symptoms or any other aspect of quality of life
measures compared to placebo. Future studies should use variable doses
of isoflavones for a longer period before ruling out beneficial
isoflavone effects in this population.