Behavior of total and free serum testosterone as a predictor for the risk of prostate cancer and its aggressiveness

Evidence for the integration of total and free testosterone levels in the management of prostate cancer

OBJECTIVE

To comprehensively assess total and calculated free testosterone levels in a consecutive group of patients with prostate cancer (PCa) and any potential impact on disease aggressiveness and recurrence outcomes.

PARTICIPANTS AND METHODS

The study included a single-centre prospective cohort of 882 patients presenting for radical prostatectomy from 2009 to 2018. Data on total testosterone (TT), sex hormone-binding globulin (SHBG), and calculated free testosterone (cFT) were prospectively collected. Stepwise logistic regression models were used to assess correlations of TT and cFT with pathological Gleason Grade Group (GGG), extraprostatic extension (EPE), seminal vesicle invasion (SVI) and biochemical recurrence (BCR).

RESULTS

Total testosterone remained nearly constant across decades (40s-80s): 0.09 decrease/year (R = 0.02), while SHBG increased 0.87/year (R = 0.32) and cFT decreased 0.08/year (R = -0.02). Low cFT of <5.5 independently predicted: very-high-risk GGG (odds ratio [OR] 0.435, 95% confidence interval [CI] 0.846-0.994; P = 0.036), EPE (OR 0.557, 95% CI 0.810-0.987; P = 0.011), SVI (OR 0.396, 95% CI 0.798-1.038; P = 0.059), and BCR within 1 year after robot-assisted radical prostatectomy (OR 0.638, 95% CI 0.971-3.512, P = 0.046). TT was not a predictor.

CONCLUSION

In contrast to popular belief, testosterone remained stable in men aged 40-80 years, whereas free testosterone decreased by 2-3%/year. Low cFT was an independent predictor of very-high-risk PCa and BCR.

Paying the price for standing tall: Fluid mechanics of prostate pathology

BACKGROUND

Age-dependent increase in the incidence of benign prostatic hyperplasia (BPH) and prostate cancer (PCa) are both related to cell proliferation and survival controlled by intraprostatic free testosterone (FT) concentration. Paradoxically, BPH and PCa occur as circulating testosterone levels decrease, so any possible relationship between testosterone levels and development of BPH and PCa remains obscure.

RESULTS

In BPH the enlarging prostate is exposed to high testosterone levels arriving directly from the testes at concentrations about hundredfold higher than systemic FT. This occurs because venous blood from the testes is diverted into the prostate due to the elevated hydrostatic pressure of blood in the internal spermatic veins (ISVs). Elevated pressure is caused by the destruction of one-way valves (clinically detected as varicocele), a unique phenomenon related to human erect posture. While standing, human males are ISVs vertically oriented, resulting in high intraluminal hydrostatic pressures-a phenomenon not found in quadrupeds. In this communication, we demonstrate the fluid mechanics' phenomena at the basis of varicocele leading to prostate pathology.

CONCLUSIONS

So far, varicocele has been studied mostly for its etiologic role in male infertility and, thus, for its effects on the testes. It is becoming clear that varicocele is a major etiologic factor in BPH and likely also in PCa. Restoring normal testicular venous pressure by treatment of the abnormal ISV's in varicocele has been shown to avert the flow from the prostate with the effect of reducing prostate volume, alleviating symptoms of BPH, and increasing concentrations of circulating FT.

Testosterone replacement therapy reduces biochemical recurrence after radical prostatectomy

OBJECTIVE

To evaluate risk of prostate cancer biochemical recurrence (BCR) after radical prostatectomy (RP) in men receiving vs not receiving testosterone replacement therapy (TRT).

PATIENTS AND METHODS

A total of 850 patients underwent RP by a single surgeon. All patients had preoperative testosterone and sex hormone-binding globulin levels determined; free testosterone was calculated prospectively. In all, 152 (18%) patients with low preoperative calculated free testosterone (cFT) levels and delayed postoperative sexual function recovery were placed on TRT and proportionately matched to 419 control patients by pathological Gleason Grade Group (GGG) and stage. Rates and time to BCR [two consecutive prostate-specific antigen (PSA) levels of ≥0.2 ng/mL] were compared in univariate and multivariate regression; Cox regression was used to generate a survival function at the mean of covariates.

RESULTS

The median follow-up was 3.5 years. There were no statistically significant differences in demographics or general health complications between groups. BCR occurred in 11/152 (7.2%) and 53/419 (12.6%) patients in the TRT and control groups, respectively. In adjusted time-to-event analysis, TRT was an independent predictor of recurrence-free survival. After accounting for GGG, pathological stage, preoperative PSA level, and cFT, patients on TRT were ~54% less likely to recur (hazard ratio 0.54, 95% confidence interval 0.292-0.997). In men destined to recur, TRT delayed time to recurrence by an average of 1.5 years.

CONCLUSION

In our experience, TRT after RP significantly reduced BCR and delayed time to BCR. There was no identifiable general health complications associated with TRT. These findings are hypothesis-generating and require confirmation with multi-centred, prospective randomised controlled trials.

A novel model to predict positive prostate biopsy based on serum androgen level

Circulating levels of prostate-specific antigen (PSA) and testosterone are widely used for the detection of prostate cancer prior to prostate biopsy; however, both remain controversial. Effective screening strategies based on quantitative factors could help avoid unnecessary biopsies. Here, we sought to clarify the predictive value of free testosterone (FT) vs total testosterone (TT) in identifying patients likely to have positive biopsies. This study aims to develop a novel model for predicting positive prostate biopsy based on serum androgen levels. This study included 253 Japanese patients who underwent prostate biopsy at our institution. TT and FT, %FT (=FT/TT), age, PSA, prostate volume (PV) and PSA density (PSAD = PSA/PV) were assessed for association with prostate biopsy findings. The following results were obtained. Of 253 patients, 145 (57.3%) had positive biopsies. Compared to the negative biopsy group, the positive biopsy group demonstrated higher age, PSA and PSAD but lower PV, FT and %FT by univariate analysis. Multivariate logistic regression analysis indicated PSA, PSAD and %FT were independent predictors of cancer detection. We developed a predictive model based on PSAD and %FT, for which the area under the curve was significantly greater than that of PSA (0.82 vs 0.66), a well-known predictor. Applying this analysis to the subset of patients with PSA <10 ng/mL yielded similar results. We confirmed the utility of this model in another independent cohort of 88 patients. In conclusion, lower %FT predicted a positive prostate biopsy. We constructed a predictive model based on %FT and PSAD, which are easily obtained prior to biopsy.

Serum testosterone as a biomarker for second prostatic biopsy in men with negative first biopsy for prostatic cancer and PSA>4ng/mL, or with PIN biopsy result

INTRODUCTION

Data from animal, clinical and prevention studies support the role of androgens in prostate cancer growth, proliferation and progression. Results of serum based epidemiologic studies in humans, however, have been inconclusive. The present study aims to define whether serum testosterone can be used as a predictor of a posi¬tive second biopsy in males considered for re-biopsy.

MATERIAL AND METHODS

The study included 320 men who underwent a prostatic biopsy in our department from October 2011 until June 2012. Total testosterone, free testos¬terone, bioavailable testosterone and prostate pathology were evaluated in all cases. Patients undergoing a second biopsy were identified and biopsy results were statistically analyzed.

RESULTS

Forty men (12.5%) were assessed with a second biopsy. The diagnosis of the second biopsy was High Grade Intraepithelial Neoplasia in 14 patients (35%) and Prostate Cancer in 12 patients (30%). The comparison of prostatic volume, total testosterone, sex hormone binding globulin, free testosterone, bioavailable testosterone and albumin showed that patients with cancer of the prostate had significantly greater levels of free testosterone (p=0.043) and bioavailable T (p=0.049).

CONCLUSION

In our study, higher free testosterone and bioavailable testosterone levels were associated with a cancer diagnosis at re-biopsy. Our results indicate a possible role for free and bioavailable testosterone in predicting the presence of prostate cancer in patients considered for re-biopsy.

Measurement of serum testosterone during androgenic suppression in patients with prostate cancer: A systematic review

INTRODUCTION

Clinical practice guidelines recommend measuring serum testosterone (ST) during androgenic suppression (AS) to assess its efficacy and define castration resistance (CR). The objectives of this systematic review were to assess the level of scientific evidence that justify checking ST levels during AS, when to perform it and for what purpose.

MATERIAL AND METHODS

We performed a search in PubMed with the following mesh terms: androgen suppression, testosterone, and prostate cancer. The search was narrowed to original articles published in English.

RESULTS

We found 8 publications that analysed the clinical impact of ST concentrations during AS. In all of the series, ST was measured using chemiluminescent assays. However, only indirect methods based on liquid or gas chromatography for its extraction and subsequent quantification using mass spectrometry are recommended, especially for measuring low levels. The endpoints were specific survival and CR-free survival. Six studies were retrospective. The series were not uniform in terms of clinical stage, types of AS and ST assessment methods. In general, low ST levels (<20ng/dL or <32ng/dL) were related to longer CR-free survival. The measurements were performed every 3 or 6 months. Four studies confirmed the beneficial effect of adding bicalutamide when detecting microelevations above 50ng/dL.

CONCLUSIONS

The level of scientific evidence justifying the measurement of ST during AS is low, and the methods employed for quantifying ST levels are inadequate. However, we consider it useful to check ST levels during AS, and there appears to be an association between low ST levels and better disease outcomes. In the event of microelevations above 50ng/dL, we recommend the administration of bicalutamide.

Association between late-onset hypogonadism syndrome plus metabolic syndrome and prostate cancer and its aggressiveness

OBJECTIVE

To assess the relationship between prostate cancer (PC) and the presence of metabolic syndrome and late-onset hypogonadism (LOH) syndrome.

MATERIAL AND METHOD

A retrospective study was conducted on 686 patients who underwent prostate biopsy. We analysed the demographic variables, clinical data and biopsy results. To diagnose metabolic syndrome, we employed the criteria of the American Heart Association. For the diagnosis of LOH syndrome, we employed the Androgen Deficiency in the Aging Male questionnaire and testosterone levels (TT). We evaluated the relationship between free testosterone (FT) and bioavailable testosterone (BT) on one hand and PC and its aggressiveness on the other, as well as the usefulness of the TT to prostate specific antigen (TT/PSA) ratio in the PC diagnosis.

RESULTS

The patient's median age was 65 years. Metabolic syndrome is not associated with PC (39.4% vs. 35%; P=.1) but is associated with a PC Gleason score >7 (50.4% vs. 29.44%; P=.002). LOH, low FT and low BT are associated with an increased presence of PC (51% vs. 35%, P=.02; 44.86% vs. 33.33%, P=.03; and 46.46% vs. 33.08%, P=.01, respectively) and with an increased probability of a PC Gleason score >7 (61.54% vs. 37.5%, P=.02; 54.17% vs. 34.12%, P=.02; 54.35% vs. 34.48%, P=.02, respectively). Additionally, the median TT/PSA ratio was significantly lower in patients with positive biopsies (P=.022).

CONCLUSIONS

Metabolic syndrome was not associated with the probability of having PC but was associated with a PC Gleason score >7. Moreover, LOH syndrome had a higher percentage of PC and a greater presence of PC Gleason scores >7, as did low levels of FT and low levels of BT.