Men diagnosed with early prostate cancer may choose to actively monitor their disease rather than to have surgery or radiotherapy, new research suggested.
The study, the largest of its kind and published this week in the New England Journal of Medicine, found all three treatments result in similar, and very low, rates of death from prostate cancer over 10 years.
It noted that surgery and radiotherapy did reduce the risk of cancer progression over time compared with active monitoring, but cause more unpleasant side-effects.
"What we have learnt from this study so far is that prostate cancer ... grows very slowly, and very few men die of it when followed up over a period of 10 years, -- around one percent -- irrespective of the treatment assigned," chief investigator Professor Freddie Hamdy from the University of Oxford, said in a statement.
"This is considerably lower than anticipated when we started the study," Hamdy said.
Between 1999 and 2009, more than 1,600 British men aged 50 to 69 whom were diagnosed with localized prostate cancer were enrolled in the ProtecT trial and they agreed to be randomized to active monitoring, radical prostatectomy or radical radiotherapy.
The research team measured mortality rates at 10 years, cancer progression and spread, and the impact of treatments reported by the patients and found survival was extremely high, at approximately 99 percent, irrespective of the treatment assigned.
The rate of cancer progression and spread was reduced by more than half to 10 percent in men in the surgery and radiotherapy groups, compared with active monitoring. However, surgery and radiotherapy caused unpleasant side-effects, particularly in the first year after treatment.
According to the researchers, there was some recovery from side-effects over two to three years. But after six years, twice as many men in the surgery group still experienced urine leakage and problems with their sex life, in comparison with those in the active monitoring and radiotherapy groups. Radiotherapy caused more bowel problems than surgery or active monitoring.
But they noted that only half of the men stayed on active monitoring over the 10-year period.
Co-investigator Professor Jenny Donovan, from the University of Bristol said this is the first time radiotherapy, surgery and active monitoring treatments for prostate cancer have been compared directly.
"The results provide patients and clinicians with detailed information about the effects and impacts of each treatment so that they can make an informed decision about which treatment to have," said Donovan.
"Each treatment has different impacts and effects, and we need longer follow up to see how those balance out over the next 10 years."
