Surgical treatment offers better survival rates than radiotherapy for most men with clinically localised prostate cancer, according to one of the largest studies of its type.
Researchers in Oxford, Stockholm, and the Netherlands compared data from more than 34,000 patients in Sweden over a 15-year period and found surgery offered improved survival rates, with greatest benefit for younger men in good general health.
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.
It is hoped the study’s results, published online today in the BMJ, could help inform treatment choice.
The researchers from Oxford University’s Nuffield Department of Surgical Sciences, the Department of Molecular Medicine and Surgery at the Karolinska Institutet in Stockholm, and the Department of Epidemiology at Erasmus University in the Netherlands, were supported by the National Institute for Health Research (NIHR) Oxford Biomedical Research Centre and the Swedish Research Council.
The lead author Prasanna Sooriakumaran, senior clinical researcher at Oxford and assistant professor at the Karolinska, said the study offered the best evidence to date on the comparative long-term outcomes of surgery and radiotherapy for prostate cancer.
But he was clear the benefits of surgery related to certain risk groups of patients with localised prostate cancer, disease that 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 the merits of each in survival terms, it can come down to personal choice based on the side effects of each option.
Mr Sooriakumaran 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.
“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.
“In addition, given the significant burden prostate cancer poses on the NHS and other healthcare systems worldwide, these findings could have important policy implications.”
Surgical treatment of prostate cancer is by radical prostatectomy, a procedure to remove the prostate gland. This can now be performed using robotic keyhole surgery. Radical radiotherapy treatment involves giving a high dose of radiation to the prostate gland.
In this study virtually all men with prostate cancer diagnosed in Sweden from 1998 onwards were followed for up to 15 years. Data from the National Prostate Cancer Registry of Sweden was merged with eight other Swedish national datasets including the Inpatient and Cause of Death registries to obtain complete and accurate information of important characteristics like tumour type, grade, stage, age, medical history, and socioeconomic status.
A number of statistical models were performed to adjust for differences at baseline between those men that had undergone surgery and those that opted for radiotherapy. All statistical models demonstrated that men who had had surgery had better survival rates than those that had undergone radiotherapy.
Peter Wiklund, the study’s senior author and professor and chairman at the Karolinska 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.
“We are confident in the robustness of our findings, but we must remember that the demographic make-up of Sweden is different to that of many parts of the world including the USA and UK, and thus how these results apply to different patient populations is yet to be determined. Nevertheless, the finding that surgery appears best in survival terms for most men with localised prostate cancer is highly compelling.”
It is important to emphasise that the findings are reported from a retrospective cohort of well-annotated patients.
In addition, teams in Oxford, Bristol and Cambridge are leading the ProtecT study in the UK, a prospective randomised controlled trial funded by the National Institute for Health Research Health Technology Assessment (HTA) programme, which is evaluating the treatment effectiveness of conventional therapies in localised prostate cancer, the results of which are awaited in 2016.