recent study of 478 men screened for prostate cancer

with transrectal ultrasound-guided biopsy, no rela-

tionship was observed between serum testosterone

level and prostate cancer severity.

Thus, it is

possible that the relationship between testosterone

level and Gleason score is indeed most significant in

older men with more aggressive tumors.

Our study was limited by several factors. First, the

study was performed with a cohort of men diag-

nosed with prostate cancer. Although the considera-

tions for questionnaire score are addressed above, it

is also possible that unaccounted for factors,

including individual differences in anxiety levels

before major surgery or as a result of the cancer

diagnosis, may have affected both IGF-1 levels and

erectile function. Second, most of the correlations,

save for those in the

70-year-old age group, are

fairly low. Although this could be a result of the

factors above, there may be additional variables that

affect the relationship between the GH axis and

sexual function and are currently unaccounted for.

Considering the overlap between GH and testos-

terone in the pathogenesis of erectile dysfunction, it

may be beneficial to evaluate both the testosterone

and GH axes when evaluating etiology and con-

sidering the treatment of erectile dysfunction. Our

results support a relationship between IGF-1 and

male sexual function, and strengthen the argument

to more closely study the role of IGF-1 in erectile

dysfunction. There do not exist sufficient data to use

IGF-1 or GH supplementation in men with erectile

dysfunction currently, and studies demonstrating a

role of GH and IGF-1 in development and progres-

sion of prostate cancer may further temper this

possibility.

However,

recent

studies,

including

ours, show potential and promise for new ways to

enhance current treatment protocols that could

improve quality of life in men with erectile

dysfunction.

Conflict of interest

The authors declare no conflict of interest.

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