There is a lack of high quality evidence to help decision making whilst choosing treatment for localised prostate cancer. In a study by Sooriakumaran et al published in BMJ (2014) the authors study 34515 Swedish men treated for prostate cancer with either surgery (n=21533) or radiotherapy (n=12982). Median follow up was over 5 years for both modalities. Mortality from prostate cancer was higher in the radiotherapy arm for patients with non-metastatic disease (subdistribution hazards ratio=1.76). Younger, fitter men with fewer comorbitities and with intermediate or high risk disease had the greatest differential benefit from surgery.
There are a number of limitations of this study, and a randomised trial comparing these two treatments is still awaited, but this probably gives the best current evidence.