Hazard of Prostate Cancer Specific Mortality After Radical Prostatectomy

Abstract

Hazard is defined as an event rate at a certain time that is conditional on survival until that time. For most patients with localized malignancies the mortality hazard decreases with time after an initial period of high failure risk. We assessed prostate cancer specific mortality hazard changes with time in men treated with radical prostatectomy. The cohort included 127,236 men from the SEER (Surveillance, Epidemiology and End Results) database who were treated with RP between 1988 and 2003. Pathological stage was organ confined in 38,684 men (30%), nonorgan confined in 41,806 (33%) and unstaged in 46,746 (37%). Gleason score 7 or less was present in 100,816 men (79%) and Gleason score 8 or greater in 26,420 (21%). Patients were stratified into groups, including group 1—71,106 (59%) with Gleason score 7 or less, organ confined, group 2—23,063 (19%) with Gleason score 7 or less, nonorgan confined, group 3—13,660 (12%) with Gleason score 8 or greater, organ confined and group 4—12,158 (10%) with Gleason score 8 or greater, nonorgan confined tumors. Median followup was 7.2 years (range 0 to 19). Hazard was estimated from a Cox regression model including patient age, race, stage and grade. The overall annual prostate cancer specific mortality hazard rate was 0.4%, 0.7% and 1% 5, 10 and 15 years after radical prostatectomy, respectively. Between 5 and 15 years after radical prostatectomy the hazard increased annually from 0.2% to 0.5% in group 1, from 0.5% to 1.2% in group 2, from 0.7% to 1.6% in group 3 and from 1.5% to 3.7% in group 4. In contrast to other prevalent cancers, the hazard of prostate cancer specific mortality shows a modest, constant increase for at least 15 years after radical prostatectomy.