Prognostic value of a cell-cycle progression score in men with prostate cancer managed with active surveillance after MRI-guided prostate biopsy--a pilot study.

BACKGROUND/AIM Initial inaccurate staging is a common problem associated with active surveillance (AS) for patients detected by transrectal ultrasound-guided prostate biopsy (TRUS-GB). Subsequently, repeated biopsies are necessary to monitor such patients. Thus, in addition to the already established clinicopathological criteria, there is a considerable demand for new, objective decision criteria to more accurately select AS candidates. Recently, a novel RNA expression signature derived from 31 cell-cycle progression (CCP) genes has been shown to be a strong predictor of outcome in patients after radical prostatectomy or radiotherapy. This is a qualitative pilot study to evaluate the prognostic value of the CCP-score (CCP-S) for the first time in men managed with AS after MRI-guided prostate biopsy (MRI-GB). PATIENTS AND METHODS Nine patients previously diagnosed with prostate cancer during an ongoing, prospective trial assessing MRI-GB with additional TRUS-GB and were subsequently managed with AS. CCP-S were retrospectively derived from biopsy specimens. The CCP-S is defined as the expression level of 31 CCP genes, normalized to 15 housekeeping genes, and is clinically validated in a range between -1.3 and 4.7. To assess the estimated 10-year mortality risk (without curative treatment), the CCP-S from each patient was combined with the individual CAPRA (Cancer of the Prostate Risk Assessment) score (CAPRA-S). RESULTS Median patient age was 72 (range=58-77) years. Mean pre-biopsy PSA level was 6.33±1.94 (range 4.23-9.97) ng/ml. Eight cases had Gleason score 6 (3+3) and one cancer had Gleason score 7 (3+4). Median CCP-S was -0.9 (range=-1.5 to 0.0). Combining CCP-S with CAPRA-S [CAPRA-S: 1 (n=4), 2 (n=4), 3 (n=1)] the estimated 10-year mortality risk was not calculable for three patients because their CCP-S [CCP-S -1.4 (n=2) and -1.5 (n=1)] was outside the validated range. For the other 6 patients the estimated 10-year mortality ranged from 1.0-3.0%. CONCLUSION The CCP-S confirms accurate staging of AS patients detected by MRI-based biopsy strategies and may significantly reduce inaccurate staging of AS patients and subsequent unnecessary re-biopsies. The CCP score may help to more accurately select for active surveillance candidates.