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.