The natural history of untreated "prostatism".

One hundred and seven patients with symptoms of prostatic obstruction in whom prostatectomy was not clinically indicated were reviewed after an interval of 5 years. Ten had subsequently required surgery and 97 remained untreated. In the majority, symptoms did not worsen and only 2 developed acute retention. Urodynamic studies, where repeated, showed little change. Although there was no certain indicator or progression, a flow rate measurement could identify the patients at risk of clinical deterioration sufficient to require surgery.