Hormone patches are as good at controlling locally advanced prostate cancer as the injections typically used to deliver hormone therapy, according to the results of a large clinical trial led by UCL (University College London) researchers.
Men with cancer that has spread just outside the prostate are given hormone therapy to suppress levels of testosterone which the cancer needs to grow. Most commonly this is done by injections of drugs that block testosterone production.
The new study, published in The New England Journal of Medicine, found that patches that lower testosterone by delivering oestradiol (a form of oestrogen) through the skin were as effective as injections at preventing the cancer from spreading, and caused fewer side effects.
The current standard of care, injections of LHRH agonists (luteinizing hormone-releasing hormone agonists), requires multiple hospital or GP visits, whereas oestradiol patches can be put on by patients at home.
In addition, side effects including hot flushes, bone density problems and risk factors for heart disease (such as higher cholesterol, blood glucose and blood pressure) were less common among men using patches compared to LHRH agonists, although breast tissue swelling was more common in the patches group.
Oestradiol patches are currently not licensed in the UK to treat prostate cancer, but the researchers hope that they will be made more easily available so men with prostate cancer have more choice of treatment.
Lead author Professor Ruth Langley (MRC Clinical Trials Unit at UCL) said: "We believe our findings should lead to men with locally advanced prostate cancer being able to choose which hormone therapy suits them best. For some men, for instance, hot flushes can be very debilitating, and so the patches could greatly increase their quality of life."
For the study, 1,360 men with locally advanced, non-metastatic prostate cancer (i.e. that had not spread to other parts of the body) were randomly assigned to receive either oestradiol patches or the current standard of care injections.
After three years or more, the research team found both treatments had similar effects in controlling prostate cancer - 87% of people in the oestradiol group were alive without their cancer spreading, compared to 86% in the standard-of-care group.
The team also compared the side effects of the two approaches. Side effects from LHRH agonists come not only from lower levels of testosterone but also from lower oestrogen levels. That is because most oestrogen in men is converted from testosterone.
Oestradiol patches add oestrogen to the body (which causes less testosterone production) so side effects related to low oestrogen levels, such as hot flushes, are much reduced.
Among those using patches, only 44% reported any hot flushes compared to 89% in the injection group. However, breast tissue swelling (gynaecomastia) was more frequent with patches, affecting 85% of participants compared to 42% of those on injections.
The number of patients experiencing bone fractures five years after entering the trial was 2.8% in those who started on oestradiol patches versus 5.8% of those started on injections.
Previous studies comparing oestradiol patches to LHRH agonists have shown that overall quality of life scores are better in men receiving the patches compared to the injections.
Simon Grieveson, Assistant Director of Research at Prostate Cancer UK, said: "Hormone therapy is an extremely common and effective treatment for prostate cancer, currently given through regular injections. But for many men it can cause quite significant side effects.
"Results from the PATCH/STAMPEDE trials have shown that hormone patches like these, delivered through the skin, are just as effective at delaying cancer progression. The skin patches also resulted in fewer men experiencing hot flushes, however breast tissue swelling was more common.
"These skin patches are more convenient and less invasive and could give men greater choice in their treatment based on what's important to them and how they live their lives."
Caroline Geraghty, senior specialist nurse manager at Cancer Research UK, said: "Prostate cancer remains the most common cancer in men in the UK - that's why we must continue to find new breakthroughs in treating the disease. Thanks to research, over 8 in 10 men diagnosed with prostate cancer will now survive for 10 years or more. As well as finding more effective treatments, we need to find ways to make them kinder too.
"This trial has done exactly that - it shows that hormone patches are just as effective as traditional injections at controlling locally advanced prostate cancer, while being much easier and gentler to administer. This should give men greater choice over their treatment in the future, allowing them to live not just longer lives, but better lives."
Dr Duncan Gilbert, a Consultant Clinical Oncologist from Sussex who recruited many patients to the trial, who is also based at the MRC Clinical Trials Unit at UCL, said: "Seeing these positive results published is a testament to all of the patients that took part in the trial and the hard work undertaken by research teams at UK hospitals over many years. The ease of administration and improved side-effect profile offers real choice for patients and I look forward to this option for testosterone suppression being available to the wider population of patients needing treatment for prostate cancer."
The oestradiol patches used in the trial are the same as those used in hormone replacement therapy (HRT) to treat symptoms of the menopause in women. These patches are currently not licensed to treat prostate cancer, meaning they need to be prescribed "off-label" (i.e. outside approved use). Some healthcare providers may be reluctant to do this.
For these patches to be approved as a prostate‑cancer treatment, a manufacturer would need to apply for a licence covering this new use. In the UK this is handled by the Medicines and Healthcare products Regulatory Agency and in the US by the Food and Drug Administration. An easier and faster option is for a company that already sells oestradiol patches for another purpose to apply to extend its existing licence so that it also covers prostate cancer.
Professor Langley said: "We hope these patches can be made more easily available to treat prostate cancer so that men have the benefit of a choice of treatment."
The participants in the study were recruited from the UCL-led PATCH and STAMPEDE trials between 2007 and 2022 from 75 centres in the UK. The study was sponsored initially by Imperial College London and then UCL and funded by Cancer Research UK and the UKRI Medical Research Council (MRC) Clinical Trials Unit.
UCL's commercialisation company, UCL Business Ltd, is currently working with Professor Langley and her team to support potential licence applications for the patches, including engaging with potential manufacturers and licence holders with the aim of the treatment becoming widely available for patients.
UK prostate cancer figures
Prostate cancer is the most commonly diagnosed cancer in the UK, and one in eight men will be diagnosed in their lifetime. Each year, more than 64,000 men are diagnosed with the disease, with around 12,000 men dying annually. The stage at which prostate cancer is detected varies across the UK, with substantial regional differences, but a significant proportion of men (between 20% and 30%) are diagnosed with locally advanced or late‑stage disease. In the UK around 540,000 men are living with or after prostate cancer.
