Heterogeneity in high-risk prostate cancer treated with high-dose radiation therapy and androgen deprivation therapy.

BACKGROUND: Our aim was to assess the heterogeneity of high-risk (HR) prostate cancer managed with high-dose external beam radiotherapy (EBRT) with androgen deprivation therapy (ADT). METHODS: We identified 547 patients who were treated with modern EBRT from 1997 to 2013, of whom 98% received ADT. We analyzed biochemical relapse-free survival (bRFS) and distant metastases-free survival (DMFS). RESULTS: Median EBRT dose was 74 Gy, and median ADT duration was 8 months. At 5 years, the DMFS was 85%. On multivariate analysis, significant predictors of shorter bRFS were biopsy Gleason score (bGS) of 8 to 10, higher prostate-specific antigen (PSA) level, shorter duration of ADT and lower radiation dose while predictors of shorter DMFS were bGS of 8 to 10, higher PSA level, and lower radiation dose. We identified an unfavorable high-risk (UHR) group of with 2-3 HR factors based on 2015 National Comprehensive Cancer Network (NCCN) criteria and a favorable high-risk (FHR) group, with 1 HR feature. Comparing very-HR prostate cancer, UHR & FHR, 5 year bRFS rates were 58.2%, 66.2%, and 69.2%, and 5 year DMFS rates were 78.4%, 81.2%, and 88.0%. CONCLUSION: Patients with multiple HR factors have worse outcome than patients with 1 HR factor. Future studies should account for this heterogeneity in HR prostate cancer.

Development of a label-free LC-MS/MS strategy to approach the identification of candidate protein biomarkers of disease recurrence in prostate cancer patients in a clinical trial of combined hormone and radiation therapy.

PURPOSE: Combined hormone and radiation therapy (CHRT) is one of the principle curative regimes for localised prostate cancer (PCa). Following treatment, many patients subsequently experience disease recurrence however; current diagnostics tests fail to predict the onset of disease recurrence. Biomarkers that address this issue would be of significant advantage. EXPERIMENTAL DESIGN: Label-free LC-MS/MS for protein biomarker discovery and MRM for targeted confirmation were applied to patient serum samples accrued in a non-interventional clinical trial of CHRT. RESULTS: Analysis of time-matched patient samples from a patient with disease recurrence compared with a time match disease-free individual supported the identification of 287 proteins. Of these, 141 proteins were quantified, 95 proteins changed in their expression (P ≤ 0.05 and ≥1.5-fold change) and of these 16 were selected for MRM confirmation. The protein expression changes observed in the label-free LC-MS/MS and MRM analysis were found to be highly correlated (R(2) = 0.85). CONCLUSIONS AND CLINICAL RELEVANCE: The establishment of a clinical trial to support the acquisition of samples and development of a pipeline for MS-based biomarker discovery and validation should contribute to the identification of a serum protein signature to predict or monitor the outcome of treatment of patients with PCa.