testosterone is essential for the normal growth and development of the prostate gland and is also a possible risk factor for prostate cancer .
huggins and hodges 's seminal work in the 1940s first demonstrated the hormone dependence of prostate cancer , consequently establishing testosterone as a key therapeutic target for managing prostate cancer .
androgen deprivation therapy to lower the serum testosterone level remains a standard treatment for advanced disease to the present day .
isbarn et al 's recent studies , however , show a result opposite that of huggins and hodges , implying that testosterone neither increases the risk of prostate cancer nor causes cancer recurrence in men who have been treated successfully for prostate cancer .
a recent study by morote et al showed that prostate cancer risk and tumor aggressiveness are unrelated to serum testosterone .
other recent epidemiologic studies also have found no association between testosterone and prostate cancer [ 6 - 10 ] . our main objective was to analyze the relationship between serum testosterone , prostate - specific antigen ( psa ) , and prostate cancer risk in high - risk patients .
the study population consisted of 120 men with a psa level of 10 ng / ml or higher .
the data were collected from january 2008 to january 2010 . to determine the relationship between testosterone , psa , and prostate cancer risk in a high - risk group , we limited our study population to men with a psa level of 10 ng / ml or higher .
we excluded from this analysis men who were taking medications known to lower psa , such as finasteride or dutasteride .
twelve cores were obtained and two extra biopsies were taken if hypoechoic or otherwise suspicious areas were noted on ultrasound .
serum testosterone levels were measured by using a solid - phase competitive chemiluminescent enzyme immunoassay with the advia centaur immunoassay system ( bayer health care , chicago , il , usa ) .
we classified the men as hypogonadal if their serum testosterone level was < 300 ng / dl , according to the criteria used by rhoden et al . for possible correlation between serum testosterone , psa , and prostate cancer , we included age , psa density ( psad ) , prostate volume , and gleason score for patients with prostate cancer .
statistical analysis was performed by using the student 's t - test , the pearson correlation test , simple linear regression , and binary logistic regression . odds ratios with 95% confidence intervals ( cis ) for psa , psad , serum testosterone , and age were determined to predict prostate cancer risk .
all data are presented as the mean2 sd to define and characterize quantitative variables and as percentages to characterize qualitative variables ; we considered a p - value<0.05 to be statistically significant .
out of 120 patients , the samples of 85 ( 70.1% ) patients were diagnosed as benign and those of 35 ( 29.2% ) patients were diagnosed as being prostate cancer .
there was no significant difference in the patient 's average age , psa , prostate volume , or testosterone between patients without and those with prostate cancer .
only psad differed significantly between the two groups ( t - test , p=0.012 ) ( table 1 ) .
hypogonadal and eugonadal men did not differ significantly in cancer detection rate ( 30.2% vs. 32.0% , respectively ) .
the testosterone level did not differ significantly between patients without and those with prostate cancer in either hypogonadal ( 248.1650.41 ng / dl vs. 251.3543.61 ng / dl , respectively ) or eugonadal ( 501.52137.06 ng / dl vs. 506.22126.40 ng / dl , respectively ) men ( t - test , p>0.05 ) .
testosterone was unrelated to age , psa , psad , or prostate volume in both men without and those with prostate cancer , and prostate cancer aggressiveness also was unrelated to serum testosterone in prostate cancer patients ( p>0.05 ) ( table 2 ) .
the binary logistic regression also confirmed that none of the variables used in this study was an independent predictor of prostate cancer risk for men with a psa level > 10 ng / ml ( p>0.05 ) ( table 3 ) .
further evaluation with simple linear regression confirmed that testosterone and psa did not show any correlation ( p>0.05 ) ( fig .
when we divided the patients into 11 groups according to their testosterone level , within a 150 ng / dl range , prostate cancer prevalence did not change as the testosterone level increased ( p>0.05 ) ( table 4 ) .
in men , the leydig cells in the testes produce approximately 90% of testosterone ; the adrenal glands produce the rest .
testosterone plays a key role in the development of male reproductive tissues such as the testes and prostate gland . under testosterone influence , the prostate gland experiences two main growth periods .
the first occurs early in puberty , when the prostate doubles in size . at around age 25 ,
when the prostate is growing , testosterone is converted into dihydrotestosterone ( dht ) , which is the androgen receptor 's major activator .
after dth binds to androgen receptors , it translocates to the nucleus , where it mediates the transcriptional activation of target genes .
these androgen - stimulated changes in gene expression promote cellular growth , which often results in benign prostatic hyperplasia in elderly men .
long - term cessation of the prostate 's exposure to androgen appears to protect against the development of cancer , but no dose - response relationship between testosterone level and cancer risk has been established .
the prostate cancer risk for men with a testosterone concentration in the normal range remains unclear .
recent chemopreventive trials with 5-alpha - reductase inhibitors show the role of testosterone in prostate cancer development .
finasteride reduced the risk of prostate cancer by 24.8% compared with a placebo in healthy men .
recently , the reduce study showed that dutasteride also reduced the risk of prostate cancer by 23% compared with a placebo in healthy men .
huggins and hodges first showed the effect of testosterone on prostate cancer patients in 1941 .
they showed the hormonal responsiveness of prostate cancer by reporting that markedly reducing the testosterone level by castration and estrogen treatment caused metastatic prostate cancer to regress , and injecting testosterone caused prostate cancer to grow . in 1995
wu et al found that the distribution of dihydrotestosterone - to - testosterone ratios parallels both the incidence of and mortality from prostate cancer .
the demonstration that androgen suppression effectively treats advanced prostate cancer , and the fact that elevated serum androgen levels might predispose people to prostate cancer , have attracted persistent interest .
however , a recent study refuted any connection between elevated testosterone levels and increased prostate cancer risk .
endogenous hormones and prostate cancer collaborative group et al meta - analyzed the serum concentrations of sex hormones from subjects in 18 prospective studies that included 3,886 men with incident prostate cancer and 6,438 control subjects .
they concluded that endogenous hormones , including testosterone , were not associated with prostate cancer .
morote et al recently conducted another study of 478 patients , all of whom were assessed by trus - guided prostate biopsy because of an abnormal digital rectal examination , psa > 4 ng / ml , or both .
they found no difference in serum testosterone level between patients with and those without prostate cancer and concluded that the serum testosterone level was not associated with prostate cancer risk or aggressiveness .
an animal study by morgentaler and traish showed that beyond a certain serum testosterone concentration , androgens have a limited ability to stimulate prostate cancer growth .
subsequent increases in serum testosterone levels beyond that concentration did not stimulate the prostate because the binding capacity of the intra - prostatic androgen receptors had been saturated .
our results are similar to those of the above studies even though we limited our study population to patients with psa > 10 ng / ml . we found that the serum testosterone level at the time of diagnosis was unrelated to psa and prostate cancer risk and aggressiveness in both hypogonadal and eugonadal patients .
ideas about the interaction between testosterone and prostate cancer have changed considerably over the past decade . like our study , most recent epidemiologic studies have found no association between testosterone and prostate cancer [ 6 - 10 ] .
a few studies published during the past decade contrast with our results , however , and show that low testosterone levels seem to be related to an increased risk of prostate cancer and tumor aggressiveness , such as a high gleason score [ 23 - 28 ] . in our study , we compared age , psa , prostate volume , and psad with testosterone .
only a known prostate cancer predictor , psad , showed a significant difference between patients with and those without prostate cancer , even in high - risk patients with a psa level of 10 ng / ml or higher .
patients without prostate cancer had relatively lower psa and larger prostates than did patients with prostate cancer .
however , our binary logistic regression showed that psad was unsuitable as an independent predictor of prostate cancer risk in men with a psa level of 10 ng / ml or higher .
we measured the serum testosterone level in the patients only once , before their biopsy was done .
second , we checked only their total testosterone level and were unable to check their free testosterone level .
, the present study found that the serum testosterone level at the time of diagnosis was unrelated to psa and prostate cancer risk and aggressiveness . because testosterone levels change with age and time , a prospective study with long - term testosterone monitoring is required to find a relationship between testosterone and prostate cancer .
our results show that the serum testosterone level at the time of diagnosis was unrelated to psa and prostate cancer risk and aggressiveness .
additional studies with long - term follow - up are needed to explain the possible mechanism and relationship between testosterone , prostate cancer , and psa .
 purposetestosterone is essential for the prostate gland 's normal growth and development and is also a possible risk factor for prostate cancer . 
 this study 's aim was to determine the significance of serum testosterone for prostate - specific antigen ( psa ) elevation and prostate cancer prediction in high - risk men.materials and methodsthe study included 120 patients with psa > 10 ng / ml who underwent a transrectal - prostate biopsy . 
 serum testosterone , prostate volume , and psa density ( psad ) were checked in all patients . 
 patients were divided into two groups , patients with and those without prostate cancer ; and testosterone - related factors , prostate volume , psa , psad , age , prostate cancer prediction rate , and cancer aggressiveness were evaluated.resultsthirty-five patients ( 30.2% ) were confirmed as having prostate cancer . the average serum testosterone level in patients without and in those with prostate cancer was 452.25154.62 ng / dl and 458.10158.84 ng / dl , respectively ; average psa was 17.589.02 ng / ml and 18.626.53 ng / ml , respectively ; and average age was 69.027.52 years and 70.697.02 years , respectively ( p>0.05 ) . hypogonadal and eugonadal 
 patients showed no significant difference in cancer prevalence ( 30.3% vs. 32.0% , respectively ) . 
 the testosterone level did not differ significantly in patients with and those without prostate cancer in either hypogonadal or eugonadal men ( p>0.05 ) . 
 serum testosterone showed no correlation with psa , psad , or age in either group ( p>0.05 ) and was unrelated to prostate cancer risk or aggressiveness ( p>0.05).conclusionsin our study 's results , serum testosterone at the time of diagnosis was unrelated to psa elevation , prostate cancer risk , and aggressiveness . 