The Influence of Androgen Deprivation Therapy on Dihydrotestosterone Levels in the Prostatic Tissue of Patients with Prostate Cancer

Vol. 10, 7121–7126, November 1, 2004 Clinical Cancer Research 7121

Featured Article The Influence of Androgen Deprivation Therapy on Dihydrotestosterone Levels in the Prostatic Tissue of Patients with Prostate Cancer

Tsutomu Nishiyama,1 Yutaka Hashimoto,2 and Conclusions: The source of dihydrotestosterone in pros- Kota Takahashi1 tatic tissue after androgen deprivation therapy involves in- 1Division of Urology, Department of Regenerative and Transplant tracrine production within the prostate, converting adrenal Medicine, Niigata University Graduate School of Medical and Dental androgens to dihydrotestosterone. Dihydrotestosterone still Sciences, Niigata; and 2Pharmaceuticals Group, Nippon Kayaku Co., remaining in prostate tissue after androgen deprivation Ltd., Tokyo, Japan therapy may require new therapies such as treatment with a combination of 5␣-reductase inhibitors and antiandrogens, ABSTRACT as well as castration. Purpose: The influence of androgen deprivation therapy on dihydrotestosterone levels in the prostatic tissue is INTRODUCTION not clearly known. Changes in dihydrotestosterone levels in Since the observation of Huggins and Hodges (1) that the prostatic tissue during androgen deprivation therapy in disseminated prostate cancer reacts favorably to castration or the the same patients have not been reported. We analyzed administration of estrogenic hormones, first-line hormonal ther- dihydrotestosterone levels in prostatic tissue before and af- apy has been used to impair the production or activity of ter androgen deprivation therapy. androgens or both. Experimental Design: A total of 103 patients who were Testosterone is converted to dihydrotestosterone by 5-␣ suspected of having prostate cancer underwent prostatic reductase in the prostate. There have been several reports that biopsy. Sixty-nine patients were diagnosed as having pros- examined in detail the method for quantitative analysis of the tate cancer whereas the remaining 34 were negative. Serum tissue dihydrotestosterone concentrations of the prostate (2–5). samples were collected before biopsy or prostatectomy. Di- Belanger et al. (5) and Labrie et al. (6) stated that after the hydrotestosterone levels in prostatic tissue and serum were elimination of testicular androgens, the intraprostatic concentra- analyzed using liquid chromatography/electrospray ionization of dihydrotestosterone remains at ϳ40%. These data indi- tion-mass spectrometry after polar derivatization. In 30 of cate that a substantial level of dihydrotestosterone remains in the the patients with prostate cancer, dihydrotestosterone levels prostate after castration. Belanger et al. (5) and Labrie et al. (6) in prostatic tissue were determined by performing rebiopsy also suggested that dihydrotestosterone completely disappears or with prostate tissues excised after 6 months on androgen from the prostate after androgen deprivation therapy with cas- deprivation therapy with castration and flutamide. tration and flutamide. The influence of androgen deprivation Results: Dihydrotestosterone levels in prostate tissue therapy on dihydrotestosterone levels in the prostatic tissue in after androgen deprivation therapy remained at ϳ25% of prostate cancer, however, is not fully known. Changes in dihy- the amount measured before androgen deprivation therapy. drotestosterone levels in the prostatic tissue during androgen Dihydrotestosterone levels in serum decreased to ϳ7.5% deprivation therapy for prostate cancer in the same patients have after androgen deprivation therapy. The level of dihydrotes- not been reported. One of the reasons is that the detectable tosterone in prostatic tissue before androgen deprivation quantity of dihydrotestosterone involved in the prostatic tissue therapy was not correlated with the serum level of testosterone. Serum levels of adrenal androgens were reduced to collected from needle biopsy samples is minute. We, however, ϳ60% after androgen deprivation therapy. have developed a detection system for minuscule quantities of dihydrotestosterone with liquid chromatography/electrospray ionization-mass spectrometry after polar derivatization of dihydrotestosterone (7). Therefore, we analyzed dihydrotestosterone levels in pros- Received 5/9/04; revised 6/26/04; accepted 8/10/04. tatic tissue and endogenous hormone levels in serum both in The costs of publication of this article were defrayed in part by the patients with prostate cancer and those without prostate cancer payment of page charges. This article must therefore be hereby marked who underwent prostatic biopsy. The patients diagnosed with advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. clinically localized prostate cancer, furthermore, were treated Requests for reprints: Tsutomu Nishiyama, Division of Urology, De- with androgen deprivation therapy in a neoadjuvant setting for 6 partment of Regenerative and Transplant Medicine, Niigata University months. We then carried out rebiopsy or prostatectomy 6 Graduate School of Medical and Dental Sciences, Asahimachi 1-757, months after androgen deprivation therapy treatment to analyze Niigata 951-8510, Japan. Phone: 81-25-227-2285; Fax: 81-25-227- 0784; E-mail: [email protected]. dihydrotestosterone levels in prostatic tissue and endogenous ©2004 American Association for Cancer Research. hormone levels in serum.

PATIENTS AND METHODS ionization was developed and applied to the sensitive analy- Patients. Between April 2000 and October 2002, 103 sis of dihydrotestosterone. Dihydrotestosterone in prostatic patients suspected of having prostate cancer underwent pros- tissue was dissolved in alkaline solution and extracted via a tatic biopsy. Those patients diagnosed with clinically local- solid-phase column and derivatized to N-methylpyridinium- ized prostate cancer were given androgen deprivation therapy dihydrotestosterone as a polar derivative. N-Methylpyri- (castration and flutamide) in a neoadjuvant setting for 6 dinium-dihydrotestosterone was purified by Bond Elut C18 months. Baseline patients’ characteristics are listed in Table and determined with a semi–micro-liquid chromatography/ 1. This research was reviewed and approved by the Institu- electrospray ionization-mass spectrometry with selected re- tional Review Board. Written informed consent was obtained action monitoring. The calibration graph was linear from 5 to from all participants. 100 pg/tube. The lowest dihydrotestosterone level in this Sample Collections. To determine dihydrotestosterone method was 5 pg/tube. levels, the samples of prostatic tissue were obtained from the Statistical Analysis. Statistical comparison of hormonal midlateral region of the prostate with a 16-gauge biopsy needle; levels in patients with prostate cancer before treatment and alternatively, prostatectomy specimens were used. Serum sam- noncancer patients at diagnosis was carried out with the Mann- ples for endocrine study were collected from the patients be- Whitney U test. Statistical comparison of DHEA level in pa- tween 9:00 and 12:00 p.m. (noon). In all patients who underwent tients with prostate cancer before treatment and noncancer pa- ultrasound-guided biopsy or radical prostatectomy, serum sam- tients at diagnosis was also carried out with a multivariate ples were obtained before the respective interventions. Serum analysis with logistic regression after forcing age in the model. samples were stored at Ϫ20°C until additionally processed. All biopsies and prostatectomy specimens were analyzed by con- Statistical comparison of the influence of androgen deprivation ventional pathological examination. Tissue samples were stored therapy on hormonal levels was carried out with the Wilcoxon’s at Ϫ80°C until additional processing. signed rank test. The correlation between the dihydrotestoster- Hormones and Prostate-specific Antigen Levels of one levels or ACTH and ACTH or other androgens was ana- Serum Samples Other Than Dihydrotestosterone. The lyzed with the Spearman rank correlation coefficient. The test prostate-specific antigen and hormones were quantified by com- was two-sided, and a P value of Ͻ0.05 was considered statis- mercially available immunoassays: prostate-specific antigen tically significant. Statistical analyses were carried out with [TOSOH-II (PA)], luteinizing hormone, and follicle-stimulating SPSS software v.11.0 for PC (SPSS, Inc., Chicago, IL). hormone. All hormones were quantified by automated fluores- cence polarization assays on Tosoh equipment (Tosoh Corpo- ration, Tokyo, Japan). Serum levels of testosterone, adrenocor- RESULTS ticorticotropic hormone (ACTH), cortisol, androstenedione, Clinical Results. Sixty-nine patients were diagnosed as dehydroepiandrosterone (DHEA), DHEA sulfate (DHEA-S), having prostate cancer and 34 as having a nonmalignant prostate and prolactin were determined by radioimmunoassay (BML, condition. The patients’ characteristics are listed in Table 1. Tokyo, Japan). Thirty of the 69 patients were treated with androgen deprivation Sensitive Analysis of dihydrotestosterone in Prostatic therapy with a luteinizing hormone-releasing hormone agonist Tissues and Serum Samples by Semi–Micro-Liquid Chro- (goserelin acetate or leuprolide acetate) or bilateral orchiectomy matography/Electrospray Ionization-Mass Spectrometry af- and flutamide in a neoadjuvant setting for 6 months. Eight of the ter Polar Derivatization. The dihydrotestosterone levels in 30 patients were withdrawn from flutamide treatment because of prostatic tissue and serum were analyzed by liquid chroma- adverse effects during the following dosing periods: 1 month, 1 tography/electrospray ionization-mass spectrometry after po- patient; 2 months, 1 patient; 4 months, 3 patients; and 5 months, lar derivatization of dihydrotestosterone, as described previ- 3 patients. Six patients were withdrawn because of liver dys- ously (7). The polar derivatization method for electrospray function and two because of diarrhea.

Table 1 Patient characteristics Total With cancer Without cancer No. of patients 103 69 34 Age (y) at diagnosis [mean (range)] 69 (41–86) 71 (45–86)* 66 (41–81)* PSA [ng/mL, median (range)] 14.9 (3.0–19578) 27.4 (4.7–19578)† 8.6 (3.0–27.8)† Gleason score [mean (range)] 6 (4–10) M0 54 M1 15 Androgen deprivation therapy 30 Age (y) at diagnosis [mean (range)] 71 (57–78) LH-RHa ϩ flutamide 25 Castration ϩ flutamide 5 Abbreviations: LH-RHa, luteinizing hormone-releasing hormone agonist. * P ϭ 0.004. † P Ͻ 0.001.

Dihydrotestosterone Levels in Prostatic Tissue and Se- Table 3 The correlation between the DHT levels and other androgens in patients with prostate cancer and noncancer patients at ؍ rum Hormone Levels in Patients with Prostate Cancer (n ϭ (at diagnosis (N 103 (34 ؍ before Treatment and Noncancer Patients (n (69 Diagnosis. In this study, the serum DHEA level was signifi- sDHT tDHT cantly lower in patients with prostate cancer by comparison with Testosterone rs ϭ 0.425 rs ϭ 0.010 noncancer patients using the Mann-Whitney U test (P ϭ 0.037; P Ͻ 0.001 P ϭ 0.923 Table 2). However, there is no statistical association between Androstenedione rs ϭ 0.254 rs ϭ 0.019 P ϭ P ϭ prostate cancer and DHEA level using results of the logistic 0.130 0.852 DHEA rs ϭ 0.305 rs ϭ 0.243 regression model (P ϭ 0.762). There were no statistically sig- P ϭ 0.003 P ϭ 0.014 nificant differences between the patients with prostate cancer DHEA-S rs ϭ 0.065 rs ϭ 0.239 and the patients without prostate cancer in LH (P ϭ 0.165), P ϭ 0.530 P ϭ 0.015 ϭ ϭ sDHT rs ϭ 0.229 follicle-stimulating hormone (P 0.206), prolactin (P ϭ ϭ ϭ P 0.025 0.169), ACTH (P 0.788), cortisol (P 0.770), testosterone tDHT rs ϭ 0.229 (P ϭ 0.539), androstenedione (P ϭ 0.509), and DHEA-S (P ϭ P ϭ 0.025 ϭ 0.404), including dihydrotestosterone levels in serum (P Abbreviations: sDHT, dihydrotestosterone level in serum; tDHT, 0.602) and prostatic tissue (P ϭ 0.302) in this study. There were dihydrotestosterone level in prostatic tissue. no statistically significant differences between the patients with prostate cancer and the patients without prostate cancer with respect to the ratios of testosterone to serum dihydrotestosterone (P ϭ 0.772) and dihydrotestosterone in prostatic tissue (P ϭ one (P Ͻ 0.001), DHEA (P ϭ 0.001), DHEA-S (P Ͻ 0.001), 0.191). and dihydrotestosterone (P Ͻ 0.001) and the level of dihydrotes- Correlation between the Dihydrotestosterone Levels tosterone in prostatic tissue (P Ͻ 0.001) significantly declined and Other Androgens in Patients with Prostate Cancer be- after androgen deprivation therapy (Table 4). The dihydrotestosterone levels in prostatic tissue after androgen deprivation ؍ fore Treatment and Noncancer Patients at Diagnosis (n 103). The level of dihydrotestosterone in prostatic tissue be- therapy, however, remained at ϳ25% of those measured before fore androgen deprivation therapy was not correlated with the androgen deprivation therapy. The dihydrotestosterone levels in serum level of testosterone (rs ϭ 0.010, P ϭ 0.923; Table 3). serum decreased to ϳ7.5% after androgen deprivation therapy. The level of dihydrotestosterone in prostatic tissue was corre- Testosterone levels decreased to ϳ2.7% after androgen depri- lated with the serum levels of DHEA (rs ϭ 0.243, P ϭ 0.014) vation therapy, and serum hormone levels were reduced to 59% and DHEA-S (rs ϭ 0.239, P ϭ 0.015). There was a small for ACTH, 52% for androstendione, 60% for DHEA, and 64% correlation between the serum level of dihydrotestosterone and for DHEA-S. The decrease in adrenal androgens in the flut- the level of dihydrotestosterone in prostatic tissue (rs ϭ 0.229, amide withdrawal cases was less significant than that in the P ϭ 0.025, y ϭ 0.001x ϩ 5.0165). The serum level of dihy- flutamide cases. The prolactin level (P ϭ 0.737) and cortisol drotestosterone was correlated with the serum levels of testos- level (P ϭ 0.148) in serum did not decline after androgen terone (rs ϭ 0.425, P Ͻ 0.001) and DHEA (rs ϭ 0.305, P ϭ deprivation therapy. 0.003). Correlation between the Dihydrotestosterone Levels or The Influence of Androgen Deprivation Therapy [Total ACTH and ACTH or Other Androgens after androgen dep- -and Flutamide rivation therapy. The level of dihydrotestosterone in pros ,(22 ؍ Months with Flutamide (n 6 ,(30 ؍ n) on Hormone Levels. The serum levels tatic tissue was correlated with the serum level of testosterone [(8 ؍ Withdrawal (n of ACTH (P Ͻ 0.001), testosterone (P Ͻ 0.001), androstenedi- (rs ϭ 0.390, P ϭ 0.033; Table 5). The level of dihydrotestos-

Table 2 Pretreatment serum hormones Patients with cancer Patients without cancer Logistic regression 95% confidence Mean (SD) Mean (SD) P analysis P Odds ratio interval Age (y) 71 (45–86) 66 (41–81) 0.004 0.015 0.928 0.874–0.986 LH (mIU/mL) 6.6 (5.8) 4.61 (2.5) 0.165 FSH (mIU/mL) 20.0 (19.4) 12.8 (6.0) 0.206 PRL (ng/mL) 10.5 (18.4) 7.0 (3.4) 0.169 ACTH (pg/mL) 42.7 (34.2) 44.3 (34.7) 0.788 Cortisol (␮g/dL) 15.3 (5.5) 15.6 (4.6) 0.770 Testosterone (ng/dL) 449.3 (170.5) 425.0 (133.0) 0.539 Androstene dione (ng/mL) 0.81 (0.41) 0.86 (0.41) 0.509 DHEA (ng/mL) 1.79 (1.26) 2.26 (1.35) 0.037 0.762 1.058 0.734–1.524 DHEA-S (ng/mL) 1169.8 (803.3) 1263.0 (876.4) 0.404 sDHT (pg/mL) 462.5 (274.6) 423.9 (243.2) 0.602 tDHT (ng/g tissue) 5.19 (2.50) 5.61 (1.96) 0.302 Testosterone/sDHT 1.27 (1.00) 1.07 (0.59) 0.772 Testosterone/tDHT 99.5 (67.8) 78.9 (44.5) 0.191 Abbreviations: sDHT, dihydrotestosterone level in serum; tDHT, dihydrotestosterone level in prostatic tissue.

Table 4 The influence of ADT [total (N ϭ 30), 6 months with flutamide (N ϭ 22), and flutamide withdrawal (N ϭ 8)] on hormone levels After ADT (N ϭ 30) 6 months with flutamide (N ϭ 22) Flutamide withdrawal (N ϭ 8) Before ADT Mean (SD) Mean (SD) Mean (SD) Mean (SD) P P P PRL (ng/mL) 8.2 (4.0) 7.6 (2.3) 8.2 (2.3) 8.4 (5.3) 0.737 0.709 0.208 ACTH (pg/mL) 48.3 (46.0) 28.3 (12.1) 28.2 (13.7) 28.4 (6.2) Ͻ0.001 0.009 0.327 Cortisol (␮g/dL) 15.3 (4.5) 15.6 (5.2) 15.9 (4.5) 13.7 (5.5) 0.148 0.182 0.715 Testosterone (ng/dL) 460.8 (192.4) 12.4 (6.8) 10.4 (5.4) 18.0 (7.6) Ͻ0.001 Ͻ0.001 0.012 Androstenedione (ng/mL) 0.81 (0.36) 0.42 (0.22) 0.38 (0.21) 0.52 (0.24) Ͻ0.001 Ͻ0.001 0.025 DHEA (ng/mL) 2.03 (1.32) 1.22 (0.76) 1.06 (0.56) 1.64 (1.09) 0.001 0.001 0.484 DHEA-S (ng/mL) 1194.9 (855.0) 761.3 (875.6) 654.7 (505.7) 1054.0 (994.9) Ͻ0.001 Ͻ0.001 0.123 sDHT (pg/mL) 503.4 (315.9) 38.0 (31.2) 33.0 (27.0) 51.8 (39.3) Ͻ0.001 Ͻ0.001 0.012 tDHT (ng/g tissue) 5.44 (2.84) 1.35 (1.32) 1.23 (1.47) 1.69 (0.77) Ͻ0.001 Ͻ0.001 0.036 Abbreviations: ADT, androgen deprivation therapy; sDHT, dihydrotestosterone level in serum; tDHT, dihydrotestosterone level in prostatic tissue.

terone in prostatic tissue was not correlated with the serum level DHEA (9). The plasma concentration of DHEA-S is 100 to 500 of androgens other than testosterone. The serum level of dihy- times higher than that of testosterone. Koh et al. (10, 11) drotestosterone was correlated with the serum levels of andro- revealed that prostate cancer cells have the ability to convert stenedione (rs ϭ 0.466, P ϭ 0.009), DHEA (rs ϭ 0.577, P ϭ adrenal androgens to dihydrotestosterone intracellularly. Mohler 0.001), and DHEA-S (rs ϭ 0.480, P ϭ 0.007). There was no et al. (8) revealed that recurrent prostate cancer tissue levels of correlation between the serum level of dihydrotestosterone and adrenal androgens were ϳ50% the levels in benign prostate. In the level of dihydrotestosterone in prostatic tissue (rs ϭ 0.013, our data, the level of dihydrotestosterone in prostatic tissue P ϭ 0.869). There was no correlation between the serum level before androgen deprivation therapy was not correlated with the of ACTH and the serum levels of androgens and the level of serum level of testosterone (Table 3). The level of dihydrotes- dihydrotestosterone in prostatic tissue. tosterone in prostatic tissue after androgen deprivation therapy was only correlated with the serum level of testosterone (Table DISCUSSION 5). The level of dihydrotestosterone in prostatic tissue before Our results showed that after androgen deprivation ther- androgen deprivation therapy was correlated with the serum apy with castration and flutamide, the dihydrotestosterone level of adrenal androgens other than androstenedione (Table 3). level in prostatic tissue remained at ϳ25% of the amount The serum dihydrotestosterone level after androgen deprivation measured before androgen deprivation therapy in the same patients. Previous reports revealed that the mean dihydrotestosterone levels in the prostate tissue treated with androgen Table 5 The correlation between the DHT levels or ACTH and deprivation therapy were between 10 and 40% of those of ACTH or other androgens after androgen deprivation therapy untreated prostrate tissue (2–5). Mohler et al. (8) showed that (N ϭ 30) the dihydrotestosterone level in recurrent prostate cancer sDHT tDHT ACTH tissue was decreased to 18% of the level in benign prostate ACTH rs ϭ 0.103 rs ϭ 0.347 tissue. Belanger et al. (5) and Labrie et al. (6) indicated that P ϭ 0.586 P ϭ 0.060 androgen deprivation therapy with castration and flutamide Testosterone rs ϭ 0.260 rs ϭ 0.390 rs ϭϪ0.014 decreases intraprostatic dihydrotestosterone to the point P ϭ 0.165 P ϭ 0.033 P ϭ 0.942 ϭ ϭ ϭ where it is undetectable. Our data, however, indicates that Androstenedione rs 0.466 rs 0.351 rs 0.326 P ϭ 0.009 P ϭ 0.057 P ϭ 0.079 flutamide acts to suppress the binding of the residual dihy- DHEA rs ϭ 0.577 rs ϭ 0.071 rs ϭ 0.080 drotestosterone to androgen receptors, not to decrease intra- P ϭ 0.001 P ϭ 0.708 P ϭ 0.674 prostatic dihydrotestosterone to undetectable levels. DHEA-S rs ϭ 0.480 rs ϭ 0.341 rs ϭ 0.017 ϭ ϭ ϭ It is not clear to what extent the testosterone and dihy- P 0.007 P 0.065 P 0.930 sDHT rs ϭϪ0.013 rs ϭ 0.103 drotestosterone in prostate tissue derives from adrenal andro- P ϭ 0.869 P ϭ 0.586 gens or other steroid precursors. Previous reports showed that tDHT rs ϭϪ0.013 rs ϭ 0.347 persistent levels of prostatic dihydrotestosterone after castration P ϭ 0.869 P ϭ 0.060 are derived from adrenal androgens in the prostate (3, 5, 8). A Abbreviations: sDHT, dihydrotestosterone level in serum; tDHT, sulfatase is present in human prostate that converts DHEA-S to dihydrotestosterone level in prostatic tissue.

therapy was correlated with serum levels of adrenal androgen necessary and sufficient to convert prostate cancer growth from (Table 5). These findings suggest that serum testosterone after a hormone-sensitive to a hormone-refractory stage and was androgen deprivation therapy mostly comes from adrenal an- dependent on a functional ligand-binding domain. Increased drogens converted in the prostatic cells. These findings could levels of androgen receptor confer resistance to antiandrogens also suggest that serum dihydrotestosterone after androgen dep- by amplifying signal output from low levels of residual ligand rivation therapy comes from adrenal androgens converted in the and by altering the normal response to antagonists (23). Lei- peripheral tissues, including the prostate. It is possible that the bowitz and Tucker (24) revealed that triple androgen blockade prostate is the major dihydrotestosterone-producing organ, and therapy followed by finasteride maintenance appears to be a the level of dihydrotestosterone in prostatic tissue is correlated promising alternative for the management of patients with clin- with the level of adrenal androgens and testosterone in prostatic ically localized or locally advanced prostate cancer. These find- tissue. These results reveal that the source of dihydrotestoster- ings and our results suggest that new therapies that target one in prostatic tissue after androgen deprivation therapy in- androgen receptor and prevent formation of androgens within volves intracrine production within the prostate to convert ad- prostate cancer cells such as treatment with a combination of renal androgens to dihydrotestosterone. antiandrogens and 5␣-reductase inhibitors can block the stimu- ϳ The serum hormone levels were reduced to 60% in lation from adrenal androgens that contributes ϳ25% of total ACTH, androstenedione, DHEA, and DHEA-S after androgen dihydrotestosterone when they are combined with testicular deprivation therapy with castration and flutamide in our study. suppression of androgens and may offer the most effective The mechanism causing the decrease of adrenal androgens after androgen deprivation therapy to prolong remission of prostate androgen deprivation therapy has yet to be determined (12–14). cancer as of now. Several investigators have shown the effects of flutamide on the plasma levels of adrenal androgens (12, 14). Flutamide alleg- edly decreases adrenal androgens after treatment by castration REFERENCES and flutamide (13, 14). Our results also showed that castration 1. Huggins C, Hodges CV. Studies on prostate cancer. Effect of cas- and flutamide reduced adrenal androgens to ϳ60%. The serum tration, estrogen and androgen injection on serum phosphatases in ACTH level after androgen deprivation therapy was not corre- metastatic carcinoma of the prostate. Cancer Res 1941;1:293–7. lated with serum adrenal androgen levels and dihydrotestoster- 2. Hammond GL. Endogenous steroid levels in the human prostate from one levels in serum and prostatic tissue. Prolactin and cortisol in birth to old age: a comparison of normal and diseased tissues. J Endo- serum did not decline after androgen deprivation therapy. The crinol 1978;78:7–19. mechanism of the suppression of adrenal androgens is specu- 3. Geller J, Albert JD. Effects of castration compared with total androgen blockade on tissue dihydrotestosterone (DHT) concentration in lated to be by flutamide having an inhibitory effect on human benign prostatic hyperplasia (BPH). Urol Res 1987;15:151–3. adrenal microsomal 17␣-hydroxylase and 17,20-lyase activities 4. Forti G, Salerno R, Moneti G, et al. Three-month treatment with a (14). long-acting gonadotropin-releasing hormone agonist of patients with A recent collaborative meta-analysis has shown that the benign prostatic hyperplasia: effects on tissue androgen concentration, 5 addition of a nonsteroidal antiandrogen (flutamide or nilut- alpha-reductase activity and androgen receptor content. J Clin Endocri- amide) to castration reduced highly significantly the risk of nol Metab 1989;68:461–8. death (all causes of death) by 8% (95% confidence interval, 5. Belanger B, Belanger A, Labrie F, Dupont A, Cusan L, Monfette 3–13; P ϭ 0.005), which translates to a small but significant G. Comparison of residual C-19 steroids in plasma and prostatic tissue of human, rat and guinea pig after castration: unique impor- improvement in 5-year survival of 2.9% over castration alone tance of extratesticular androgens in men. J Steroid Biochem 1989; (15). Most meta-analyses show a positive result with nonsteroi- 32:695–8. dal antiandrogens (16). The percentage of PSA responses has 6. Labrie F, Belanger A, Dupont A, Luu-The V, Simard J, Labrie C. been shown to be significantly higher among patients receiving Science behind total androgen blockade: from gene to combination androgen deprivation therapy composed of castration and flut- therapy. Clin Investig Med 1993;16:475–92. amide than among patients undergoing castration only (17). 7. Nakagawa Y, Hashimoto Y. Polar derivatization of 5 alpha-dihy- Labrie et al. (18) showed long-term and continuous androgen drotestosterone and sensitive analysis by semimicro-LC/ESI-MS. J Mass Spectrum Soc Jpn 2002;50:330–6. deprivation therapy could offer the possibility of long-term control or possible cure of localized prostate cancer. It is estab- 8. Mohler JL, Gregory CW, Ford OH 3rd, et al. The androgen axis in recurrent prostate cancer. Clin Cancer Res 2004;10:440–8. lished that 5␣-reductase inhibitor such as finasteride can reduce 9. Bartsch W, Klein H, Schiemann U, Bauer HW, Voigt KD. Enzymes intraprostatic levels of dihydrotestosterone (19). Visakorpi et al. of androgen formation and degradation in the human prostate. Ann NY (20) showed that amplification of the androgen receptor gene is Acad Sci 1990;595:53–66. increased during androgen deprivation therapy. Gregory et al. 10. Koh E, Kanaya J, Namiki M. Adrenal steroids in human prostatic (21) showed that the androgen receptor is transcriptionally ac- cancer cell lines. Arch Androl 2001;46:117–25. tive in recurrent prostate cancer and can increase cell prolifer- 11. Koh E, Noda T, Kanaya J, Namiki M. Differential expression of ation at the low levels of androgen that occur after androgen 17beta-hydroxysteroid dehydrogenase isozyme genes in prostate cancer deprivation therapy. Zegarra-Moro et al. (22) revealed that and noncancer tissues. Prostate 2002;53:154–9. therapies that target the androgen receptor directly with an 12. Balzano S, Cappa M, Migliari R, et al. The effect of flutamide on basal and ACTH-stimulated plasma levels of adrenal androgens in patients with androgen receptor antibody or androgen receptor ribozymes advanced prostate cancer. J Endocrinol Investig 1988;11:693–6. inhibited growth of both androgen-sensitive and androgen- 13. Ayub M, Levell MJ. Suppression of plasma androgens by the refractory prostate cancer in vitro. Chen et al. (23) revealed that antiandrogen flutamide in prostatic cancer patients treated with Zoladex, the increase in androgen receptor mRNA and protein was both a GnRH analogue. Clin Endocrinol (Oxf) 1990;32:329–39.

14. Carlstrom K, Pousette A, Stege R. Flutamide has no effect on dihydrotestosterone in men with benign prostatic hyperplasia. J Clin adrenal androgen response to acute ACTH stimulation in patients with Endocrinol Metab 1992;74:505–8. prostatic cancer. Prostate 1990;17:219–25. 20. Visakorpi T, Hyytinen E, Koivisto P, et al. In vivo amplification of 15. Prostate Cancer Trialists’ Collaborative Group. Maximum androgen the androgen receptor gene and progression of human prostate cancer. blockade in advanced prostate cancer: an overview of the randomised Nat Genet 1995;9:401–6. trials. Prostate Cancer Trialists’ Collaborative Group. Lancet 2000;355: 21. Gregory CW, Johnson RT Jr, Mohler JL, French FS, Wilson EM. 1491–8. Androgen receptor stabilization in recurrent prostate cancer is 16. Klotz L. Combined androgen blockade in prostate cancer: meta- associated with hypersensitivity to low androgen. Cancer Res 2001; analyses and associated issues. BJU Int 2001;87:806–13. 61:2892–8. 17. Eisenberger MA, Blumenstein BA, Crawford ED, et al. Bilateral 22. Zegarra-Moro OL, Schmidt LJ, Huang H, Tindall DJ. Disruption of orchiectomy with or without flutamide for metastatic prostate cancer. androgen receptor function inhibits proliferation of androgen-refractory N Engl J Med 1998;339:1036–42. prostate cancer cells. Cancer Res 2002;62:1008–13. 18. Labrie F, Candas B, Gomez JL, Cusan L. Can combined androgen 23. Chen CD, Welsbie DS, Tran C, et al. Molecular determinants of blockade provide long-term control or possible cure of localized prostate resistance to antiandrogen therapy. Nat Med 2004;10:33–9. cancer? Urology 2002;60:115–9. 24. Leibowitz RL, Tucker SJ. Treatment of localized prostate cancer 19. McConnell JD, Wilson JD, George FW, Geller J, Pappas F, Stoner with intermittent triple androgen blockade: preliminary results in 110 E. Finasteride, an inhibitor of 5 alpha-reductase, suppresses prostatic consecutive patients. Oncologist 2001;6:177–82.

Downloaded from clincancerres.aacrjournals.org on October 2, 2021. © 2004 American Association for Cancer Research. The Influence of Androgen Deprivation Therapy on Dihydrotestosterone Levels in the Prostatic Tissue of Patients with Prostate Cancer

Tsutomu Nishiyama, Yutaka Hashimoto and Kota Takahashi

Clin Cancer Res 2004;10:7121-7126.

Updated version Access the most recent version of this article at: http://clincancerres.aacrjournals.org/content/10/21/7121

Cited articles This article cites 24 articles, 6 of which you can access for free at: http://clincancerres.aacrjournals.org/content/10/21/7121.full#ref-list-1

Citing articles This article has been cited by 19 HighWire-hosted articles. Access the articles at: http://clincancerres.aacrjournals.org/content/10/21/7121.full#related-urls

E-mail alerts Sign up to receive free email-alerts related to this article or journal.

Reprints and To order reprints of this article or to subscribe to the journal, contact the AACR Publications Subscriptions Department at [email protected].

Permissions To request permission to re-use all or part of this article, use this link http://clincancerres.aacrjournals.org/content/10/21/7121. Click on "Request Permissions" which will take you to the Copyright Clearance Center's (CCC) Rightslink site.