Testosterone Treatment in Prostate Cancer Survivors With Hypogonadism: A Randomized Clinical Trial

Testosterone restored sex drive in prostate cancer survivors, with zero recurrences in 136 men over 12 weeks

Journal: JAMA Internal Medicine | Published: 2026-07-01 | Type: Randomized Controlled Trial, Phase II, Multicenter | PMID: 42113507 Authors: Bhasin Shalender et al. (Research Program in Men's Health, Aging and Metabolism, Boston Claude D. Pepper Older Americans Independence Center; with Burnett Arthur L, Brady Department of Urology, Johns Hopkins School of Medicine) Funding/COI: Not listed in the indexed record

Summary

Bhasin et al., 2026 ran a placebo-controlled trial giving weekly testosterone injections to 136 men with low libido, erectile dysfunction, or fatigue after radical prostatectomy for low-grade prostate cancer. Testosterone increased sexual activity, desire, and several physical measures over 12 weeks, and none of the 136 men had a PSA rise during the trial. The authors are explicit that this is a proof-of-concept study, not evidence of long-term safety.

Claims

• Testosterone increased sexual activity by 0.91 events/day more than placebo (95% CI, 0.56-1.26; P < .001)
• Testosterone increased sexual desire, prostate cancer quality-of-life sexual domain score, and reduced negative affect versus placebo
• Erectile function did not differ between groups
• Testosterone improved body composition, loaded stair-climbing power, and VO2 peak versus placebo
• 0 of 136 men (68 testosterone, 68 placebo) had biochemical recurrence (PSA ≥ 0.2 ng/mL) during the trial
• 125 of 136 randomized men (92%) completed the study

Study Quality

This is a double-blind, placebo-controlled, block-randomized phase 2 trial, stratified by age and PDE5I use, run at two academic centers and registered on ClinicalTrials.gov (NCT03716739). Randomization and blinding reduce the usual bias risks, and the primary outcome (sexual activity) reached a tight, clearly reported effect estimate.

The bigger issue is what the trial was actually built to detect. Enrollment required a strict, narrow population: low-grade cancer only (Gleason 6 or 7), undetectable PSA for 2+ years post-surgery, no androgen deprivation or radiation therapy. That's a favorable-prognosis subgroup by design, and the authors say outright the findings don't generalize beyond it. The safety endpoint was biochemical recurrence over 12 weeks of treatment - a short window and a surrogate marker, not clinical recurrence, metastasis, or mortality, which is what actually matters for a treatment historically considered contraindicated in this population.

Red Flags

• Funding source and conflicts of interest are not disclosed in the indexed record, which is a real gap for a trial evaluating a treatment with commercial stakes
• Safety follow-up is only 12 weeks; the authors themselves state the trial is "neither long enough nor large enough to evaluate clinical recurrence or long-term safety"
• Enrollment window ran 2019 to 2025 for only 136 patients across 2 sites, suggesting slow recruitment, though the paper doesn't explain why
• Findings apply only to a narrow, favorable subgroup (low-grade cancer, no ADT/radiation) and cannot be extended to men with more aggressive disease

Strengths

• Randomized, double-blind, placebo-controlled design with concealed allocation
• Stratified randomization for age and PDE5I use
• Multicenter, registered trial with a prespecified primary outcome
• High completion rate (92%)
• Authors are transparent about the trial's limitations rather than overselling a phase 2 result

Verdict

This is a methodologically sound small trial that answers a narrow question well: in men with favorable-prognosis, surgically treated prostate cancer, 12 weeks of testosterone didn't trigger a PSA rise and improved several quality-of-life measures. It is not evidence that testosterone is safe long-term in prostate cancer survivors generally, and the authors say so themselves. Worth reading for the trial design and the sexual-activity effect size, worth ignoring if the takeaway you're looking for is "testosterone is safe after prostate cancer."