Scientists say a new drug which treats aggressive prostate cancer is possibly the most significant development in the field for 70 years.
The new drug Abiraterone could they say potentially treat up to 80% of patients with a deadly form of the disease which is resistant to currently available chemotherapy.
Abiraterone works by blocking the hormones which fuel the cancer and is a major step forward in the treatment of end-stage prostate cancer patients.
Prostate cancer is the most common cancer among men and each year, 680,000 men worldwide are diagnosed with the disease and about 220,000 will die from it.
On the assumption that the cancer was driven by sex hormones such as testosterone produced in the testicles, current treatments aim to stop the testicles from producing testosterone.
Now experts have discovered that the cancer can feed on sex hormones from all sources, including supplies of the hormone produced by the tumour itself.
Abiraterone targets an enzyme called CYP17, which plays a key role in this process and works by blocking production of the hormones throughout the body.
An advanced clinical trial involving 1,200 patients around the world is currently under way, with more trials likely later this year.
The latest study is based on just 21 patients with advanced, aggressive prostate cancer who were treated with a 'once-a-day' pill.
The study found significant tumour shrinkage, and a drop in tell-tale levels of a key protein produced by the cancer called prostate specific antigen in the majority of patients.
Many of the patients, who have been monitored for up to two-and-a-half years, have reported a significant improvement in the quality of their lives and some were able to stop taking morphine for the relief of pain caused by the spread of the disease to their bones.