From November 1994 through January 2002, researchers from the Minneapolis Veterans Affairs Health Care System and other healthcare facilities in the United States randomly assigned 731 men with localized prostate cancer to undergo radical prostatectomy or observation. They extended follow-up through August 2014 for the primary outcome of the study, all-cause mortality, and the main secondary outcome, prostate-cancer mortality.
During 19.5 years of follow-up (median, 12.7 years), death occurred in 223 of 364 men (61.3%) who underwent radical prostatectomy and in 245 of 367 (66.8%) who were observed. Death attributed to prostate cancer or its treatment occurred in 27 men (7.4%) assigned to surgery and in 42 men (11.4%) assigned to observation. Treatment for disease progression was less frequent with surgery than with observation. Urinary incontinence and erectile and sexual dysfunction were each greater with surgery than with observation through 10 years of follow-up.
The researchers concluded that after nearly 20 years of follow-up of men with localized prostate cancer, radical prostatectomy was not associated with significantly lower all-cause or prostate-cancer mortality than observation. The study findings are available here