Radical prostatectomy improves survival in selected metastatic prostate cancer patients: A North American population-based study

Objective: To test whether radical prostatectomy might result in better survival than external beam radiation therapy in metastatic prostate cancer patients. Methods: Newly diagnosed metastatic prostate cancer patients with M1a/b substages, treated with radical prostatectomy or external beam radiation therapy were abstracted from the Surveillance, Epidemiology and End Results database (2004–2016). Temporal trend analyses, propensity score matching, cumulative incidence plots, multivariate competing risks regression models and landmark analyses were used. Results: Of 4280 patients, 954 (22.3%) were treated with radical prostatectomy. After propensity score matching, 5-year cancer-specific mortality was 47.0 versus 53.0% in radical prostatectomy versus external beam radiation therapy patients (P = 0.003). In propensity score matched competing risks regression models, radical prostatectomy was associated with lower cancer-specific mortality versus external beam radiation therapy (hazard ratio 0.79, 95% confidence interval 0.79–0.90; P = 0.001). Finally, landmark analyses rejected the bias favoring radical prostatectomy. Finally, in subgroup analyses, we relied on selection criteria that most closely resembled the STAMPEDE criteria and a similar hazard ratio of 0.8 (P < 0.001) was recorded. Conclusion: In metastatic prostate cancer, radical prostatectomy results in lower cancer-specific mortality relative to external beam radiation therapy. Even after adjustment for age at diagnosis, prostate-specific antigen and biopsy Gleason grade grouping, lower cancer-specific mortality rates are recorded in radical prostatectomy patients than in external beam radiation therapy patients. As a result, radical prostatectomy should be considered as a treatment option in selected metastatic prostate cancer patients. However, further validation will be provided by ongoing clinical trials.