The following article features coverage from the American Urological Association (AUA) 2019 meeting. Click here to read more of Renal & Urology News’ conference coverage.

CHICAGO—Achieving lower testosterone levels in patients placed on continuous androgen deprivation therapy (ADT) for advanced prostate cancer (PCa) may delay development of castration-resistant disease, study findings presented at the 2019 American Urological Association annual meeting suggest.

Testosterone levels below 50 ng/dL traditionally have been considered castration-levels, but investigators found that achieving levels below 20 ng/dL at 6 months after ADT initiation predicted a significant 45% decreased risk of progressing to castration-resistant PCa (CRPC) compared with higher levels.

A team led by Bobby Shayegan, MD, of McMaster University in Hamilton, Ontario, Canada, studied 116 men who initiated continuous ADT at a tertiary care center. They stratified patients according to absolute testosterone levels measured at 6 months following ADT initiation. The median follow-up was 48 months.

At 6 months, 57 men had absolute testosterone levels below 20 ng/dL and 59 had higher levels. The groups did not differ significantly in median age (69 vs 68 years) or median pretreatment PSA level (both 7 ng/mL).

Results showed that 71.6%, 21.6%, 3.4%, and 3.4% of patients achieved a 1-year mean testosterone level below 20, 20–32, 32–50, and 50 ng/dL or higher, respectively. Most patients (58.6%) progressed to CRPC, with a median time to progression of 20 months.

Patients who had an absolute testosterone level below 20 ng/dL at 6 months had a significantly increased median time to castration-resistant disease compared with those whose level was 20 ng/dL or higher (48 vs 24 months), Dr Shayegan and his colleagues reported.

Read more of Renal & Urology News’ coverage of the AUA 2019 meeting by visiting the conference page.

Reference

Ding M, Lee T, Di Lena R, Shayegan B. Investigating the impact of a lower testosterone threshold on castration-resistant progression in patients on continuous androgen deprivation therapy. Presented at the 2019 American Urological Association annual meeting held May 3-6 in Chicago. Abstract MP22-04.