Men with localised prostate cancer were unlikely to die in the 10 years after diagnosis regardless of whether they chose surgery, radiation or no intervention at all, researchers said.
The findings in the New England Journal of Medicine included more than 1 600 men aged 50-69 who agreed to be randomly assigned to either surgery to remove the tumor, radiation to shrink it or active monitoring a wait and see approach.
About one percent of men in the study died within 10 years of prostate cancer, "irrespective of the treatment assigned, a rate that was considerably lower than was anticipated when the trial commenced," said the study, led by Freddie Hamdy of Oxford University.
Of the 1 643 men in the study, 17 died of prostate cancer in the next decade after diagnosis eight in the active monitoring group, five in the surgery group and four in the radiotherapy group.
Those in the active-monitoring group were more likely to see the cancer spread elsewhere in the body, a process known as metastasis.
However, this disease progression did not make for significant differences in the likelihood of dying from cancer or any other cause in the 10 years after diagnosis, the study said.
A separate article in the same journal examined quality of life issues among the men who chose different options.
Surgery to remove the prostate had the greatest negative effect on sexual function and urinary incontinence, it found.
Men in the radiation group tended to experience more bowel problems after treatment than the other groups.
"Sexual function appears to be better in the radiation therapy group," said Louis Potters, chairman of the department of radiation medicine at Northwell Health in New York, who was not involved in the study.
Potters praised the research as "the first real effort to assess treatment approaches for prostate cancer."
"Despite the high prevalence of prostate cancer as the number one cancer in men, there has not recently been a study that has directly addressed observation, surgery or radiation therapy," he added.
"As a result, men have had to make treatment decisions based on non-comparative data."
For John Burn, professor of clinical genetics at Newcastle University, the study provides "valuable information for men faced with difficult choices."
"The bottom line seems to be that for these men with localised prostate cancer, active monitoring is not significantly more dangerous and avoids the potential burden of medically induced sexual or bowel impairment," added Burn, who was not involved in the study.
"Many will conclude that doing nothing is preferable to surgery or radiotherapy. Obviously if there is evidence of spread the situation is different."