24th Int'l Prostate Cancer Update: Abstract - Cell cycle progression-combined risk score stratifies prostate cancer risk and significantly modifies treatment decisions in prostate cancer


VAIL, CO USA (UroToday.com) - Background: The cell cycle progression combined risk (CCP-CR) test (Prolaris™, Myriad Genetic Laboratories, Inc.) has been validated in eight cohorts and provides information on the risk of prostate cancer-specific disease progression and disease specific mortality when combined with standard clinicopathologic parameters.

In this analysis, we evaluated how the CCP score modified the AUA risk in results from our initial commercial testing. We also queried clinicians’ judgment regarding the clinical utility of the CCP-CR test in a prospective registry.

24th cap updateMethods: Our current laboratory database was evaluated for patients whose biopsy was tested with the CCP-CR test and whose clinicopathologic data was collected by the ordering physician. Formalin fixed, prostate biopsy tissue from 1853 patients diagnosed with adenocarcinoma was analyzed. The CCP score was calculated by measuring the RNA expression of 31 cell cycle progression genes normalized to 15 housekeeping genes. A relative classification of cancer aggressiveness was developed to interpret how the patient’s CCP score compared to that of patients within the same AUA risk category. In addition, clinicians ordering the CCP-CR test commercially were asked to complete a survey regarding their treatment recommendations before and after they received the CCP-CR test result.

Results: Of the 1 853 samples that contained sufficient carcinoma (> 0.5mm linear extent), 1 813 (97.8%) provided quality RNA for analysis. This retrospective analysis showed a normal distribution for the CCPCR score ranging from −2.9 to 3.1. Correlation with Gleason score was r=0.35. Based on the CCP score, 28.96% of men had a less aggressive cancer compared to the clinicopathologic prediction and were assigned to a lower risk group while 26.64% of patients had a more aggressive cancer. Currently, 102 clinicians have completed surveys on the influence of the CCP-CR test in 174 cases. In 65% of cases [95% CI: 58%-72%], there was a change recorded between the therapy initially planned and the therapy actually selected. In 68 of 174 cases [39%; 95% CI 32%-47%], clinicians indicated they would reduce the intended therapeutic burden post CCP-CR test. The CCP-CR test influenced treatment selection to a ‘High’ or ‘Very High’ degree in 58% cases and had “Low” or “No” influence in only 11% of cases.

Conclusion: The CCP-CR test is a novel assay that can improve risk stratification for men with prostate adenocarcinoma independent of the Gleason score and PSA level. Over 50% of men initially tested in the commercial assay were assigned to a different risk category than predicted by their clinicopathologic features alone. Based on the judgment of ordering physicians, the CCP-CR score appears to add meaningful new information to risk assessment for localized prostate cancer patients. Test results led to major changes in treatment decisions with a significant increase in conservative management options, including active surveillance or watchful waiting.

Presented by Michael K. Brawer, E. David Crawford, Neal Shore, Peter Scardino, John W. Davis, Jonathan Tward, Lowndes Harrison, Ashok Kar, Mark Scholz, Jeffery Fegan, Kelsey Moyes, Rajesh Kaldate, Lisa Fitzgerald, and Steven Stone at the 24th International Prostate Cancer Update - February 19 - 22, 2014 - Cascade Conference Center - Vail, Colorado USA