PURPOSE: Ligand-mediated activation of the androgen receptor (AR) is critical for prostate cancer (PCa) survival and proliferation.
The failure to completely ablate tissue androgens may limit suppression of PCa growth. We evaluated combinations of CYP17A and 5-α-reductase inhibitors for reducing prostate androgen levels, AR signaling, and PCa volumes.
PATIENTS AND METHODS: Thirty-seven men with intermediate/high-risk clinically localized PCa were randomly assigned to goserelin combined with dutasteride (ZD), bicalutamide and dutasteride (ZBD), or bicalutamide, dutasteride, and ketoconazole (ZBDK) for 3 months before prostatectomy. Controls included patients receiving combined androgen blockade with luteinizing hormone-releasing hormone agonist and bicalutamide. The primary outcome measure was tissue dihydrotestosterone (DHT) concentration.
RESULTS: Prostate DHT levels were substantially lower in all experimental arms (0.02 to 0.04 ng/g v 0.92 ng/g in controls; P < .001). The ZBDK group demonstrated the greatest percentage decline in serum testosterone, androsterone, and dehydroepiandrosterone sulfate (P < .05 for all). Staining for AR and the androgen-regulated genes prostate-specific antigen and TMPRSS2 was strongly suppressed in benign glands and moderately in malignant glands (P < .05 for all). Two patients had pathologic complete response, and nine had ≤ 0.2 cm3 of residual tumor (defined as a near-complete response), with the largest numbers of complete and near-complete responses in the ZBDK group.
CONCLUSION: Addition of androgen synthesis inhibitors lowers prostate androgens below that achieved with standard therapy, but significant AR signaling remains. Tissue-based analysis of steroids and AR signaling is critical to informing the search for optimal local and systemic control of high-risk prostate cancer.
Written by:
Mostaghel EA, Nelson PS, Lange P, Lin DW, Taplin ME, Balk S, Ellis W, Kantoff P, Marck B, Tamae D, Matsumoto AM, True LD, Vessella R, Penning T, Hunter Merrill R, Gulati R, Montgomery B. Are you the author?
Fred Hutchinson Cancer Research Center; University of Washington; Veterans Affairs Puget Sound Health Care System, Seattle, WA; Dana-Farber Cancer Institute, Harvard Medical School; Beth Israel Deaconess Medical Center, Boston, MA; University of Pennsylvania, Philadelphia, PA.
Reference: J Clin Oncol. 2013 Dec 9. Epub ahead of print.
doi: 10.1200/JCO.2012.48.6431
PubMed Abstract
PMID: 24323034
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