Metastatic progression following multimodal therapy for unfavorable-risk prostate cancer.

Abstract

Identifying the optimal management of unfavorable-risk (Prostate Cancer Risk Stratification [ProCaRS] high intermediate-, high-, and very high-risk categories) non-metastatic prostate cancer is an important public health concern given the large burden of this disease. We compared the rate of metastatic progression-free survival among men diagnosed with unfavorable-risk non-metastatic prostate cancer who were initially treated with radiation therapy or radical prostatectomy. Information was obtained from medical records at two academic centers in Canada from 333 men diagnosed with unfavorable-risk non-metastatic prostate cancer between 2007 and 2012. Median followup was 90.4 months. Men were eligible for the study if they received either primary radiation therapy (n=164) or radical prostatectomy (n=169), in addition to various adjuvant and salvage therapies when deemed clinically appropriate. Patients were matched on prognostic covariates using two matching techniques. Multivariable Cox proportional hazards models were used to estimate the hazard ratios (HR) and confidence intervals (CI) for metastatic progression-free survival between groups. After matching, treatment groups were balanced on prognostic variables except for percent core positivity. Hazard ratios from all Cox proportional hazards models (i.e., before and after matching, and with and without multivariable adjustment) showed no difference in the rate of metastatic progression-free survival between groups (adjusted unmatched HR 1.16, 95% CI 0.63, 2.13, p=0.64). Metastatic progression-free survival did not differ between men diagnosed with unfavorable risk non-metastatic prostate cancer who were treated with either radiation therapy or radical prostatectomy.