Stratification of risk for patients with prostate cancer at biopsy using CCP score.

Abstract

127 Background: In the US, most prostate cancers are treated with surgery or radiation, despite many having low malignant potential. If low cancer progression risk can be established, some men can be spared treatment. PSA, Gleason score and clinical stage work well for population risk assessment but lack precision for individuals. Molecular analysis can refine risk assessment as demonstrated by a cell cycle progression score (CCP) predictive of prostate cancer aggressiveness in 4 separate cohorts. In these studies, CCP typically ranged from −2 to +3 with each 1−unit increase corresponding to approximately a doubling of risk. We characterized the CCP distribution using recent samples from a typical US urology multi−centered clinical setting and determined the analytic success rate of the assay. Methods: Formalin fixed, prostate biopsy tissue from 300 patients diagnosed with adenocarcinoma within the last 12 months was analyzed. CCP is calculated by measuring the relative RNA expression of 31 cell cycle progression genes. Patients were recruited from 15 geographically diverse community urology practices. Results: CCP could be measured for 98% of samples (294/300). This study showed a normal distribution for the CCP ranging from −2 to 3.2 (median = −0.3, SD=0.92). There was little correlation of CCP with PSA, age, or body mass index. Correlation with Gleason score was similar to those in prior studies (r=0.494). A relative classification of cancer aggressiveness based on CCP of ~ 1200 patients from multiple cohorts has been developed. The 294 evaluable patients were cross−classified by AUA risk and cancer aggressiveness (see table). CCP further stratified patients within each AUA risk classification. Conclusions: CCP is a novel assay that can facilitate risk stratification for men with prostate adenocarcinoma. [Table: see text]