Following radical prostatectomy, success of adjuvant and salvage radiation therapy (RT) is dependent on the absence of micrometastatic disease. However, reliable prognostic/predictive factors for determining this are lacking.
Therefore, novel biomarkers are needed to assist with clinical decision-making in this setting Enumeration of circulating tumor cells (CTCs) using the regulatory-approved CellSearch System (CSS) is prognostic in metastatic prostate cancer We hypothesize that CTCs may also be prognostic in the post-prostatectomy setting
Patient blood samples (n=55) were processed on the CSS to enumerate CTCs at 0, 6, 12 and 24 months after completion of RT CTC values were correlated with predictive/prognostic factors and progression-free survival
CTC status (presence/absence) correlated significantly with positive margins (increased likelihood of CTC(neg) disease; P=0 032), and trended toward significance with the presence of seminal vesicle invasion (CTC(pos); P=0 113) and extracapsular extension (CTC(neg); P=0 116) Although there was a trend toward a decreased time to biochemical failure (BCF) in baseline CTC-positive patients (n=9), this trend was not significant (hazard ratio (HR)=0 3505; P=0 166) However, CTC-positive status at any point (n=16) predicted for time to BCF (HR=0 2868; P=0 0437)
One caveat of this study is the small sample size utilized (n=55) and the low number of patients with CTC-positive disease (n=16) However, our results suggest that CTCs may be indicative of disseminated disease and assessment of CTCs during RT may be helpful in clinical decision-making to determine, which patients may benefit from RT versus those who may benefit more from systemic treatments Prostate Cancer and Prostatic Disease advance online publication, 4 August 2015; doi:10 1038/pcan 2015 36
Prostate cancer and prostatic diseases 2015 Aug 04 [Epub ahead of print]
L E Lowes, M Lock, G Rodrigues, D D'Souza, G Bauman, B Ahmad, V Venkatesan, A L Allan, T Sexton
1] Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada [2] London Regional Cancer Program, London Health Sciences Centre, London, Ontario, Canada , 1] London Regional Cancer Program, London Health Sciences Centre, London, Ontario, Canada [2] Department of Oncology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada , 1] London Regional Cancer Program, London Health Sciences Centre, London, Ontario, Canada [2] Department of Oncology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada , 1] London Regional Cancer Program, London Health Sciences Centre, London, Ontario, Canada [2] Department of Oncology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada , 1] London Regional Cancer Program, London Health Sciences Centre, London, Ontario, Canada [2] Department of Oncology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada , 1] London Regional Cancer Program, London Health Sciences Centre, London, Ontario, Canada [2] Department of Oncology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada , 1] London Regional Cancer Program, London Health Sciences Centre, London, Ontario, Canada [2] Department of Oncology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada , 1] Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada [2] London Regional Cancer Program, London Health Sciences Centre, London, Ontario, Canada [3] Department of Oncology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada , 1] London Regional Cancer Program, London Health Sciences Centre, London, Ontario, Canada [2] Department of Oncology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada [3] Medical Biophysics, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada