Transdermal oestradiol patches are just as effective as luteinising hormone–releasing hormone (LHRH) agonists at treating locally advanced prostate cancer and cause fewer side effects, a new study has found.
Published in The New England Journal of Medicine and conducted by researchers at University College London (UCL), the phase 3 randomised trial ran across 75 centres in the UK between 2007 and 2022 and recruited 1,360 patients with locally advanced, non-metastatic prostate cancer.
Participants were randomised to receive either transdermal oestradiol patches, which delivered 100 μg of oestradiol every 24 hours, or the standard injectable hormone therapy of LHRH agonists.
The primary outcome was three-year metastasis-free survival. The non-inferiority margin was 4 percentage points, corresponding to a target hazard ratio of 1.31. Secondary outcomes included castrate levels of testosterone (<1.7 nmol per litre), overall survival and safety.
Efficacy and safety of transdermal oestradiol patches
The study found that after three years, metastasis-free survival was 87.1% with transdermal oestradiol and 85.9% with LHRH agonists, which met the non-inferiority criteria.
The researchers also compared the side effects of the two approaches. Among those using the patches, 44% reported hot flushes compared to 89% in the injection group. However, breast tissue swelling – known as gynaecomastia – was more frequent with the patches, affecting 85% of participants compared to 42% of those on injections.
The researchers also found that fewer patients in the patch group experienced bone fractures within five years — 2.8% compared with 5.8% in the injection group.
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.
Professor Ruth Langley, professor of oncology and clinical trials at the Medical Research Council (MRC) Clinical Trials Unit at UCL, and lead author of the recent study, 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.’
More convenient, less invasive prostate cancer treatment choice
Dr Duncan Gilbert, consultant clinical oncologist at University Hospitals Sussex NHS Foundation Trust and associate professor in cancer and clinical trials at UCL’s MRC Clinical Trials Unit, who recruited many patients to the trial, added: ‘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.’
Indeed, oestradiol patches are currently not licensed in the UK to treat prostate cancer and currently require an off-label prescription, but the researchers are hopeful that they will soon be made more easily available so men with prostate cancer have more choice of treatment.
Commenting on the trial results, Caroline Geraghty, senior specialist nurse manager at Cancer Research UK, said: ‘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.’
Other recent research has uncovered systemic gaps in prostate cancer care for men with intellectual disabilities, meaning they face significant inequalities throughout the entire prostate cancer care pathway.
A version of this article was originally published by our sister publication The Pharmacist.