Hormone patches are as effective as hormone injections for people with non-metastatic prostate cancer
16 Sep 2024
Oestradiol patches are as good as standard hormone injections at treating prostate cancer which has not yet spread elsewhere in the body, according to new results from the PATCH and STAMPEDE trial networks, run by the MRC Clinical Trials Unit at UCL.
This could increase the treatment options available for people with prostate cancer who are starting long-term androgen deprivation therapy.
These results were presented today at the 2024 European Society for Medical Oncology (ESMO) Congress in Barcelona, Spain.
Prostate cancer is the second most common cancer in the UK and the most common cancer in men. More than 50,000 people were diagnosed with prostate cancer in England in 2022. Of these, around 10,000 had high-risk or locally-advanced, non-metastatic disease, meaning the cancer had not yet spread beyond the prostate but was at high risk of doing so.
Prostate cancer needs the hormone testosterone to grow. Prostate cancer which has either already spread or is at high risk of doing so is usually treated with androgen deprivation therapy, a type of hormone therapy designed to lower the body's testosterone levels. The most common forms of this are called LHRH analogues (LHRHa), given via an injection.
Standard hormone therapy injections can cause a range of long-term side effects. A very common side effect is hot flushes, which can have an enormous impact on quality of life. Other side effects include thinning of the bones, which may lead to them becoming fragile (osteoporosis) and more likely to break. Hormone therapy injections may also increase the risk of developing diabetes or heart disease in the future.
An alternative way of giving hormone therapy is through transdermal oestradiol patches. They contain a hormone called oestradiol, which can enter the body by passing through the skin. Oestradiol also lowers the body’s testosterone levels. Researchers therefore believed that oestradiol patches may be able to treat prostate cancer in a similar way to standard hormone injections, without causing some of the side-effects.
The PATCH and STAMPEDE trials aimed to find out whether hormone patches were as good as standard-of-care hormone therapy injections, in terms of how long people lived without their cancer spreading and how long they lived overall.
The results presented today at ESMO included data from the PATCH trial and the transdermal oestradiol (tE2) comparison of the STAMPEDE trial.
Across both trials, 1,360 people with non-metastatic prostate cancer took part. Researchers randomly split participants into two groups: 639 people received the current standard-of-care LHRHa injections, while 721 people received transdermal oestradiol patches.
As part of their standard treatment, some participants also received radiotherapy to the prostate and chemotherapy using the drug docetaxel in addition to hormone therapy.
After following all participants for at least three years and some for over 15 years, the trials found that hormone patches were as good as standard-of-care hormone therapy injections at treating non-metastatic prostate cancer.
There was very little difference between the two groups in terms of how long people lived overall and how long they lived without their cancer spreading. After three years, 91% those using hormone patches were alive and 87% alive without their cancer spreading. Among those having standard hormone therapy injections, 90% were alive after three years, and 86% alive without their cancer spreading.
The results also show that in both groups, 85% of participants receiving the treatment were able to sustain testosterone levels below <1.7nmol/L (the recommended target for the treatment of prostate cancer) during the first year.
Researchers continued to monitor participants’ prostate specific antigen (PSA) levels throughout the trial. Raised PSA levels in the blood can indicate that the cancer has grown.
The trials found that those who started hormone therapy using patches could safely switch to standard-of-care injections if their PSA levels began to rise, with no negative impacts on their health.
There were some differences in side-effects between the two groups. Hot flushes were much less common among those using patches. Overall, 44% of the patch group reported having any hot flushes, compared to 89% of the injection group. However, 85% of participants using hormone patches experienced some breast tissue swelling (gynaecomastia), compared to 42% of those receiving standard-of-care injections.
Previous results from the PATCH trial have shown that oestradiol patches improve bone density, have similar levels of cardiovascular side-effects, and improve overall quality of life compared to standard hormone therapy injections.
Hormone patches could increase the treatment options available for people with prostate cancer, allowing them to choose a hormone therapy approach that is best suited to them individually, in terms of the side-effects profile and how the treatment is delivered.
The next step is for medicines regulators and the NHS to look at this evidence and decide whether transdermal oestradiol patches can be licensed for use in prostate cancer.
The participants in this study were recruited between 2007 and 2022 from 75 centres in the UK. The study was sponsored by University College London and funded by Cancer Research UK and the UKRI Medical Research Council Clinical Trials Unit.
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