Purpose: It remains controversial whether external beam radiation therapy with a brachytherapy boost provides oncologic outcomes equivalent to those of radical prostatectomy with or without adjuvant radiation therapy in men with Gleason 9-10 prostate cancer. We compared external beam radiation therapy plus brachytherapy to radical prostatectomy plus adjuvant radiation therapy for Gleason 9-10 prostate cancer in terms of overall survival and prostate cancer specific mortality in 2 large national databases.
Materials and methods: Using the NCDB (National Cancer Database) and the SEER (Surveillance, Epidemiology, and End Results) database, we identified 4,367 and 2,276 patients, respectively, diagnosed with clinical T1-T3N0M0, Gleason 9-10, prostate specific antigen 0 to 40 ng/ml prostate cancer treated with external beam radiation therapy plus brachytherapy or radical prostatectomy plus adjuvant radiation therapy. We compared overall survival and prostate cancer specific mortality using inverse probability of treatment weighted multivariable Cox proportional hazards regression modeling after accounting for clinical and demographic factors.
Results: Median followup in the NCDB and SEER cohorts was 6.0 years and 5.8 years, respectively. In the NCDB cohort there was no significant difference in 5-year overall survival between radical prostatectomy plus adjuvant radiation therapy vs external beam radiation therapy plus brachytherapy (86.7% vs 87.0%, AHR 1.10, 95% CI 0.95-1.27, p=0.220). Results were unchanged when including only patients who received androgen deprivation therapy. In the SEER cohort there was no difference in 5-year prostate cancer specific mortality (6.0% vs 5.7%, AHR 1.22, 95% CI 0.0.88-1.71, p=0.234). There was no significant interaction between patient age (65 years or greater vs less than 65) and treatment modality in the NCDB or SEER cohorts.
Conclusions: In men with Gleason 9-10 prostate cancer multimodality surgical therapy is equivalent to external beam radiation therapy plus brachytherapy.
Keywords: brachytherapy; mortality; prostatectomy; prostatic neoplasms; radiotherapy.