Patients enrolled in the study had follow-up exams every 6 months for the first 2 years of the study, followed by annual exams. The primary study end points included death from prostate cancer or any cause and metastasis. There was a blinded, independent committee that made the determinations of cause of death.
A total of 695 patients enrolled in the study: 347 men in the RP group and 348 men in the watchful waiting group. By the end of 2017, 553 (80%) of the men enrolled in the study had passed away. Of these patients, 181 (32%) had deaths attributed to prostate cancer: 71 (39%) in the RP group compared with 110 (61%) in the watchful waiting group.
At 23 years of follow-up, the cumulative incidence of death was higher in the watchful waiting group (83.8%) compared with that of the RP group (71.9%) (difference, 12%, 95% CI, 5.5-18.4). This equates to a RR of death of 0.74 (95% CI, 0.62-0.87, P <.001). Similarly, the cumulative incidence of death from prostate cancer at 23 years was higher in the watchful waiting group (31.3%) compared with the RP cohort (19.6%) (difference, 11.7%, 95% CI, 5.2-18.2) with RR of 0.55 (95% CI, 0.41-0.74). Within the RP group, a Gleason score of 8 or 9 and extracapsular extension were the key predictors of death from prostate cancer. Overall, there was a mean of 2.9 years of life gained in the RP group at 23 years of follow-up.
Not surprisingly, the cumulative incidence of distant metastases was higher in the watchful waiting group compared with the RP group (43.3% and 26.6%, respectively; (difference, 16.7%, 95% CI, 9.6-23.7). This translated to a RR of 0.54 (95% CI, 0.42-0.70, P < 0.001). The reductions in mortality and metastases when comparing RP with watchful waiting were more striking in patients who were younger than 65 years. These younger patients in the RP group had more significant decreases in overall mortality (15%), mortality due to prostate cancer (15.1%), and metastasis risk (18.6%).
This study highlights several key points. After a long-term follow-up of 23 years, patients who were assigned to the RP group had lower incidences of overall mortality, mortality secondary to prostate cancer, and metastases risk. These lower incidences were associated with a mean gain of 2.9 years. The benefit of mortality reduction seen in the RP group was more prominent in patients who had longer life expectancies and subsequent follow-up.
This study had several strengths including the long-term follow-up, randomized design, number of patients and sites, and the fact that a blinded independent committee determined patient cause of death in each case. It is important to consider that this study was not conducted in the US, therefore, the results may not be entirely reproducible in our current patient population.
In addition, there were no safety or quality of life (QoL) data included in this study. Although there was a mean gain of life among patients in the RP group, it would be interesting to see if those patients had a worse QoL based on some of the potential complications associated with RP, such as ED or urinary incontinence. A comparison of the costs between the 2 groups would also be interesting to evaluate in the future. Hopefully, this study will help facilitate discussions between the patient and that individual’s health care practitioner and help them personalize treatment approaches.
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