Androgen receptor levels appear to predict ADT response

Levels of five androgen receptors in prostatectomy specimens appear to predict which men will progress in their disease and which will respond to androgen deprivation therapy.

Using tissue samples from 63 men who underwent radical prostatectomy and subsequently underwent androgen deprivation therapy after biochemical recurrence or clinical progression, researchers at Memorial Sloan-Kettering Cancer Center, Columbia University, and Aureon Laboratories, applied quantitative immunofluorescence and spectral imaging techniques to assay for androgen receptor content, clinicopathologic variables, and other biomarkers.

Men in the study had an average PSA of 14.34 ng/mL before prostatectomy, and the majority had a prostate Gleason score ≤7. Twenty-two had seminal vesicle invasion, 11 had positive lymph nodes, 34 had positive margins, and 29 had extracapsular extension.

Of 11 immunofluorescence features related to outcomes, five were found to significantly predict time to progression. Two of the five features, androgen receptor intensity within AMACR(+) and AMACR(-) epithelial cells, demonstrated an association between elevated androgen receptor levels and shortened time to castrate rise in PSA. Of the 63 men, 32 experienced a castrate rise in PSA after ADT.

"Our findings on androgen receptor levels in this study and previous research provide an indication and an understanding of both response to therapy and progression of disease," said Michael Donovan, MD, PhD, of Aureon Laboratories, Yonkers, NY. "They also provide the basis for an interesting hypothesis that androgen receptor levels in the prostatectomy sample, determined by quantitative immunofluorescence, may be used to identify men at high risk for progression or ADT failure, and thereby have an impact on the therapeutic plan and monitoring plan."

The study was presented at the 2007 American Society for Clinical Oncology annual meeting in Chicago.