Study co-author Jennifer Rider of the Harvard School of Public Health and assistant professor of medicine at Brigham and Women's Hospital, and colleagues at the Uppsala University Hospital in Sweden used data from the Scandinavian Prostate Cancer Group Study Number 4.
The study randomized 695 men with early prostate cancer to treatment with surgery or watchful waiting with no initial treatment, with follow-up for up to 24 years.
Over the course of the study, 200 of 347 men in the surgery group and 247 of 348 men in the watchful waiting group died. Of the deaths, 63 in the surgery group and 99 in the watchful waiting group were due to prostate cancer, the study said.
Watchful waiting became an option for some with prostate cancer because those with slow-growing prostate cancer will often die of another cause before the prostate cancer becomes acute and many who have surgery -- along with radiation -- can suffer for the rest of their life with incontinence and erectile dysfunction.
However, the researchers cautioned men in Sweden are not screened with prostate-specific antigen tests, so the study results might not apply to the United States, where prostate cancer is often detected earlier.
"The latest results from the trial indicated that surgery can not only improve survival, especially in men diagnosed at a younger age or with intermediate-risk disease, but also that surgery can reduce the burden of disease in terms of development of metastases and the need for palliative treatment," Rider said in a statement.
"However, a large proportion of men in the trial still alive 18 years later did not require initial surgery or any subsequent therapy, pointing to the potential benefits of active surveillance strategies to limit over treatment."
The findings were published in the New England Journal of Medicine.