NASHVILLE -- Testosterone replacement remains controversial in men who have been treated for prostate cancer, but new data from New York's Memorial Sloan Kettering Cancer Center (MSKCC) reported here may provide some reassurance that "low T" treatments at least are safe in this population.
Among 1,563 men treated for high-risk prostate cancer at MSKCC and followed for up to 15 years, cancer recurrence rates were similar in men with low testosterone levels who took androgen replacement therapy to those in men with untreated low T and men with normal testosterone levels, reported Helen Bernie, DO, of Indiana University Health in Indianapolis.
And in a related study that included men with Gleason 6 and 7 prostate cancers, treated with radical prostatectomy, testosterone replacement begun 9 months after surgery showed no evidence of harm in ongoing follow-up (mean treatment duration of just over 3 years thus far), according to MSKCC's Carolyn Salter, MD.
Both studies were presented at the Sexual Medicine Society of North America's annual meeting.
"We believe that we have shown that testosterone therapy is not dangerous in these men, which has obvious clinical implications," said Salter, who added that -- given the absence of long-term safety data on testosterone treatment in prostate cancer patients -- larger and longer multicenter studies are still needed.
Bernie, who participated in the recurrence-rate study as a fellow at MSKCC, explained that it involved patients who underwent radical prostatectomy with high-risk prostate cancer, defined as Gleason 6/7 with unfavorable pathology, with positive surgical margins, lymph node involvement, and seminal vesicle involvement. Men with Gleason scores of 8 or higher with any pathology status were also eligible for recruitment. Biochemical recurrence was defined as a PSA level of ≥0.1 ng/mL.
Men were considered to have low testosterone if they had two or more morning blood test readings of less than 300 ng/dL.
In all, 1,119 (72%) men experienced biochemical recurrence at some point in 15-year follow-up, including 67% in the normal testosterone group, 80% in the untreated low T group, and 41% of men in the group with low T treated with replacement therapy.
After covariate adjustment, neither low T itself nor testosterone replacement therapy were associated with biochemical recurrence.
"These data suggest that patients with high-risk prostate cancer with low testosterone who were treated with testosterone therapy had no higher rates of biochemical recurrence," Bernie said.
Salter's study followed 360 men who have been prescribed testosterone therapy in the months following radical prostatectomy. To be considered for therapy, men had to have organ-confined disease and undetectable PSA post surgery. Men who opted for treatment had their testosterone doses titrated to achieve a serum level of 500-600 ng/dL, and PSA was checked every 6 months.
The men continue to be followed, and Salter noted that the mean time on testosterone therapy at last follow-up was 38 months. A single patient had a PSA recurrence, roughly 2.5 years after surgery.
Responding to an audience question after the presentations, MSKCC urologic surgeon John P. Mulhall, MD -- who helped establish the center's testosterone replacement therapy program more than a decade ago -- acknowledged that the treatment's long-term safety hasn't been completely established.
"We don't have enough data, but what we do have is a negotiated decision with our patients," Mulhall said. "We document in their chart that they have been made aware of the absence of long-term safety data, and that they accept that."
Disclosures
The researchers in both studies reported no funding source nor relevant disclosures.