Delivering oestrogen through skin patches may offer a safer and easier way to treat prostate cancer than current hormone therapies, says new research from the UK.

The study, published online in Lancet Oncology this week, finds that HRT (hormone replacement therapy) patches normally given to women to treat symptoms of menopause, lowered testosterone in men with prostate cancer to the same extent as LHRHa injections.

The Cancer Research UK trial was led by researchers at Imperial College London and the Medical Research Council (MRC) Clinical Trials Unit in London.

Lead author Ruth Langley, from the MRC Clinical Trials Unit, says in a statement:

"These promising new findings suggest that we might be able to use oestrogen patches or an oestrogen gel to treat prostate cancer without significantly increasing the risk of heart disease and stroke."

In many cases, testosterone can speed up prostate cancer that is starting to spread. Treatments that reduce levels of testosterone in advanced prostate cancer can slow tumor growth and even shrink it.

Current treatment relies on injecting LHRHa drugs to lower the amount of testosterone made by the testicles. But these can lead to serious side effects, including osteoporosis, bone fractures and diabetes.

An older treatment, that was around in the 1960s, used oestrogen pills to block testosterone production, but this causes blood clots and stroke in men.

However, this study suggests when delivered via skin patch, oestrogen does not cause the same degree of heart and blood clotting problems in prostate cancer patients as it does in tablet form.

For the trial, Langley and colleagues compared treatment via LHRHa injections to that of using oestrogen skin patches in 254 men with prostate cancer that was either locally advanced or had spread.

The results showed that the HRT patches appeared to block testosterone production as effectively as LHRHa injections.

Importantly, the patches did not cause the same blood clotting problems seen with oestrogen tablets, and neither did they have the side effects associated with LHRHa injections.

Plus, 12 months later, compared with the men treated with HRT patches, the men treated with LHRHa injections had higher levels of blood glucose and cholesterol, known risk factors for heart disease.

Langley says they think the reason oestrogen in tablet form leads to such adverse effects is because when given orally it reaches the liver in high concentrations, straight from the stomach. By administering the hormone via skin patches, you avoid the effect on the liver.

Kate Law, director of clinical and population research at Cancer Research UK, says thanks to advances in research and treatment, more men are surviving prostate cancer today than ever before, but "we still urgently need to find more effective treatments and reduce side effects".

"This trial is an important step towards better and kinder treatments that could bring big benefits to men with prostate cancer in the future," she adds.

The researchers are now going to carry out a bigger trial with 660 men to study the long-term effectiveness and safety of the patches.

Senior author Paul Abel, professor and honorary consultant in urology at Imperial College Healthcare, says they hope to have early results later this year.

Two elderly prostate cancer patients from London who were treated with the patches, spoke favourably of the treatment.

John Reynolds, 90, says he was offered a choice between injections or patches three years ago when he was diagnosed. "I chose patches and it's been a marvellous treatment - within a month or two I had no pain or blood".

Richard Dudley, 88, says he didn't want radical surgery and opted for the patches as the easier option. "When I started, my PSA was 100, but now it's around 6-7, which has made me very happy".

A study published recently in the Journal of Virology describes how a modified virus, that targets and kills all types of prostate cancer cells and leaves normal cells untouched, is showing promise as a cancer treatment that avoids the side effects that normally accompany hormonal treatment and chemotherapies.



CRUK | Health | Oestrogen Patches Could Offer a New Treatment for Prostate Cancer (cancerresearchuk)

Written by Catharine Paddock PhD