Skin patches which deliver oestrogen into the blood may be a cheaper, safer and better alternative to current hormone therapies for prostate cancer suggests a new Imperial College London study.
The preferred treatment for prostate cancers is injections of a drug, LHRHa, which reduces the production of both oestrogen and testosterone.
However, this has side effects similar to the menopause in women - resulting in poor bone health and diabetes.
Oral oestrogen pills are also used to treat prostate cancer.
Both oestrogen and testosterone are very similar chemically, so ramping up the levels of oestrogen in the body can reduce the amount of testosterone produced - and slow prostate cancer growth.
However, taking oral oestrogen pills caused significant health problems by overdosing the liver. The organ then produced chemicals, which caused blood clots, heart attacks and strokes.
So, the researchers believe that oestrogen patches may be a better option to current hormone treatments.
"We're not claiming this is equivalent to current therapies yet, but it does look like we are getting castration levels of testosterone," said Prof Paul Abel, from Imperial College London.
Prof Abel noted that their next step is to test if the oestrogen patches are as effective at stopping the growth of prostate cancer as the current hormone treatments.
He said that they now testing this in over 600 patients.