A mid-point clinical trial has determined that giving androgen deprivation therapy (ADT) via a transdermal hormone patch may be as effective as outdated injections or implants but is less likely to cause side effects in prostate cancer patients. Scientists, who were at the 2025 ASCO Genitourinary Cancers Symposium in San Francisco, find that estradiol patches would improve patient prognosis and quality of life.

Key Points:
Innovative Hormone Therapy Approach:

• Prostate cancer cells need male hormones such as testosterone in order to proliferate.

• ADT suppresses androgen receptors and decreases production of testosterone, usually by injections or implants.

• Estradiol patches, a type of transdermal estrogen treatment, provide a promising alternative.

Study Findings:

• 79 patients with prostate cancer were assigned at random to receive either LHRH medication (standard care) or an estradiol skin patch.

• At six months, 61% of the patients in both groups showed positive responses, as measured by prostate-specific antigen (PSA) levels.

• Fewer side effects were experienced by patients who used estradiol patches, including:

• Hot flashes: 5% among estradiol patch users versus 24% among LHRH drug users.

• High blood pressure: 5% among estradiol patch users versus 17% among LHRH drug users.

• However, breast enlargement occurred more often with the estradiol group.

Benefits of Estradiol Patches:

• Suppresses testosterone without estrogen depletion.

• Improves bone density and metabolic health.

• Eliminates risks of blood clots from oral estrogen.

• Economical compared to standard ADT drugs.

Quotes from Researchers:

• Dr. Nick James, Institute of Cancer Research, The Royal Marsden NHS Foundation Trust:

"Transdermal estradiol could offer an alternative to LHRH drugs for the management of prostate cancer by reducing side effects without losing efficacy."

• Dr. James on Drug Repurposing:

"This kind of repurposing of an older, low-cost drug is a significant means of enhancing outcomes above and beyond creating new therapies."

While it is currently too early to determine if estradiol patches will have a similar long-term survival benefit as LHRH drugs, the study indicates in a positive direction a viable alternative for patients experiencing considerable side effects from standard ADT. Future trials will again decide whether estradiol patches are a role that belongs in standard therapy of prostate cancer.