Robot-assisted radical prostatectomy versus volumetric modulated arc therapy: Comparison of front-line therapies for localized prostate cancer.

Abstract

Although radical prostatectomy and external beam radiotherapy are recognized as comparable treatment options for localized prostate cancer, robot-assisted radical prostatectomy (RARP) and volumetric modulated arc therapy (VMAT) as the leading respective techniques have yet to be compared. We retrospectively analyzed 860 patients with cT1-4N0M0 prostate cancer who underwent RARP (n = 500) or VMAT (n = 360) between 2011 and 2016. Biochemical recurrence-free survival (bRFS; two consecutive prostate-specific antigen measurements ≥0.2 ng/ml for RARP and Phoenix definition for VMAT) and radiological recurrence-free survival (rRFS; radiologically diagnosed distant metastasis or local recurrence) were compared between the two modalities. Cox proportional hazards model was used for multivariate analysis. The median follow-up durations were 30 and 47.5 months, and median ages were 67 and 71 years (both P < 0.0001) in the RARP and VMAT groups, respectively. VMAT patients had significantly better bRFS than RARP patients, though their definitions of biochemical recurrence differed. If a unified definition of biochemical recurrence (two consecutive prostate-specific antigen measurements ≥0.2 ng/ml) was applied, RARP patients had significantly better bRFS than VMAT patients. Regarding rRFS, RARP patients had significantly better outcomes than VMAT patients, however, multivariate analysis together with D'Amico's risk classification, age-adjusted Charlson's comorbidity index, and concomitant androgen-deprivation therapy, demonstrated no significant difference between RARP and VMAT. The rRFS outcomes of RARP and VMAT after a medium-term follow-up period were similar, despite their different patient backgrounds. Further studies with a longer follow-up period are needed to compare these techniques in terms of cancer-specific and overall survivals.