Thousands of men with aggressive and incurable prostate cancer could gain years of life with a ground-breaking new drug, British researchers say.

Eight out of ten patients with advanced prostate cancer - which kills 10,000 men a year - may see their tumours shrink and be relieved of pain simply by taking a daily pill even if their disease has spread around the body, the study suggests.

Some men taking abiraterone have survived for more than twice as long as expected when all other treatments failed, suggesting that the most common cancer in men may in future become a manageable chronic disease.

Scientists are also starting trials of the drug for sufferers of breast cancer to see if it has similar benefits.

Survival rates for common cancers such as breast and colon cancer have more than doubled in 60 years, and experts predict that, with this new drug, prostate cancer has the potential to join this list.

About 35,000 Britons have prostate cancer diagnosed each year. Many of the cancers do not spread and can be managed by surgery or monitoring.

Nearly all fatal cases are aggressive forms that are resistant to current treatments and are fuelled by testoster-one, the “male” sex hormone. After chemotherapy and radiotherapy have failed, the typical survival period is just one year or 18 months.

Johann de Bono, who led the study at the Institute of Cancer Research and the Royal Marsden Hospital, London, said that 250 men worldwide with advanced cases had so far taken the new drug - some for as long as 32 months, indicating that it could even tually boost survival by many years. The study, published today in the Journal of Clinical Oncology, found benefits for 21 patients with advanced prostate cancer. Trials are continuing.

Dr de Bono said he hoped that the new drug could be licensed and available for treatment of advanced disease within three years. He suggested that it could eventually make chemotherapy obsolete. “This is potentially a major step forward,” he said. “These men have very aggressive prostate cancer, which is exceptionally difficult to treat and almost always fatal. We hope that abiraterone will eventually offer them real hope of an effective way of managing their condition and prolonging their lives.”

Karol Sikora, a leading cancer specialist, described the study as a “significant piece of work”. He said: “We now can make people live with cancer. It’s not curable but we can keep people alive to the extent that they will die of something else. Most people affected by cancer are over 60, so if we can give them an extra 10 to 15 years that is as good as can be. We have to take into account the variability of some forms of hormone-driven cancer - this is not 100 per cent effective - but to be able to treat some of the worst cases, and grant them extra years of life, is a very positive thing.”

Advanced prostate cancer is typically treated with a form of chemical or surgical castration to block production of the male hormones. Abiraterone blocks the generation of these hormones in the testes and elsewhere in the body, including the generation of hormones in the cancer itself.

The pill decreased the size of tumours in 70 to 80 per cent of men with advanced prostate cancer, the researchers said. Patients also recorded large falls in prostate specific antigen levels in the blood - a key indicator of prostate cancer.

“Current treatments can be horrible, and carry side-effects such as loss of libido, but in some cases the cancer seems immune to therapy and carries on accelerating,” Dr de Bono said. “We believe that the cancer cells can make their own hormone ‘fuel’ to grow and survive. We believe we now have a drug that can block the ability of the cancer to make that fuel.”

An international study aims to recruit 1,200 men with advanced prostate cancer. The drug is also being used to treat breast cancer in women through a preliminary trial funded by Cancer Research UK.

Dr de Bono said: “It was able to help patients whose cancer had spread to the bones, liver, even lung. A number of patients were able to stop taking morphine for the relief of bone pain, and they got their quality of life back. In the wider context we eventually aim to make chemotherapy obsolete.”

Malcolm Mason, Cancer Research’s prostate cancer expert, said that the results were exciting but the studies were small and it was too early to say what role the drug might have in treating those with earlier stages of cancer.