Surgery offers better survival rates for most men with localised prostate cancer than radiotherapy, according to one of the largest studies of its type.
The study, led by an Oxford University researcher, found that surgery as the first-line treatment offered greatest benefits for younger men in good general health.
The international research team from the UK, Sweden and the Netherlands compared data on what happened to more than 34,000 Swedish men over a 15-year period after they had been treated for prostate cancer.
It is hoped the findings, published online today in the British Medical Journal, could help inform treatment choice.
Around 350,000 men are diagnosed with prostate cancer in Europe each year and the lifetime risk of being diagnosed is one in six. In the UK alone, more than 110 men are diagnosed every day.
Surgical treatment of prostate cancer involves a procedure to remove the prostate gland, which can now be performed using robotic keyhole surgery. Radiotherapy gives a high dose of radiation to the prostate gland.
Lead author Prasanna Sooriakumaran, from Oxford University's Nuffield Department of Surgical Sciences, said the study offered the best evidence to-date to compare the long-term outcomes of surgery and radiotherapy for prostate cancer.
But he was clear that the benefits of surgery related only to certain groups of patients with localised prostate cancer, where the disease had not spread to other parts of the body.
Mr Sooriakumaran, who is also a consultant surgeon at Oxford's Churchill Hospital, said: 'The study found that patients in what we would class as an intermediate or high-risk group who had surgery as their primary treatment had an increased survival rate.
'Benefits for surgery were also seen in low-risk prostate cancer patients but these men tended to do well whatever treatment they received.
'Further, the greatest benefits for surgery over radiotherapy were seen in younger men and those in better general health as these men were less likely to succumb to death from other causes and thus their prostate cancer became a life-threatening issue for them.'
The decision on whether to have surgery or radiotherapy is one for the patient and their consultant. At present, without clear evidence to compare what happens to patients in the long term, it can come down to personal choice based on the side effects of the treatments.
'We hope this study will play an important part in informing the decision-making process of the individual patient and his doctor regarding what treatment is best for him,' said Mr Sooriakumaran.
But he added: 'It is important that the results of this study are placed in the context of that overall discussion as to the most appropriate treatment for any given individual sufferer. We only looked at length of life and that in itself is only one consideration in choosing a treatment option.
'The side effects of different treatments will affect quality of life in different ways and some patients will value certain quality of life advantages for one treatment option as being more important than length of life.'
In this study virtually all men with prostate cancer diagnosed in Sweden from 1998 onwards were followed for up to 15 years using information from national databases. The researchers found that all the statistical models they used with the data demonstrated that men who had had surgery had better survival rates than those that had undergone radiotherapy.
Peter Wiklund, the study's senior author from Karolinska Institutet, said: 'The Swedish dataset we employed in this study is the world's most comprehensive and accurate data in survival outcomes for men with prostate cancer.'
While noting that there may be differences between Sweden and other parts of the world, including the the USA and UK, he added: 'Nevertheless, the finding that surgery appears best in survival terms for most men with localised prostate cancer is highly compelling.'
The study was funded by the National Institute for Health Research (NIHR) Oxford Biomedical Research Centre and the Swedish Research Council.