Performance of Primary Circulating Prostate Cells to Detect Clinically Significant Prostate Cancer

The aim of the study was to determine the performance of primary circulating prostate cell (CPC) detection and its comparison with recognised diagnostic parameters to determine the need for a prostate biopsy in men with an elevated total Prostate specific antigen (PSA).

Prospective study of all males who had their first prostate biopsy because of high total serum PSA. We calculated the free percent PSA, PSA velocity, and PSA density. Standard immunocytochemistry was used to identify primary CPCs. A positive test for CPCs was defined as one cell PSA (+) P504S (+) in an 8 ml blood sample. Positive and negative predictive values, specificity, and sensitivity were determined for each test, as well as the number of biopsies avoided and cancers missed. The study included 303 men, with 113/303 (37.3%) having prostate cancer. The free percent PSA was the best of the three PSA-based metrics, with a sensitivity of 70.8% and a specificity of 67.4%. Primary CPC detection had an 88.5% sensitivity and an 88.4% specificity, eliminating 181 (59.7%) biopsies, detecting 93/95 (98%) clinically important malignancies, and omitting 13 (11.5%) low grade, small volume tumours.

The use of primary CPCs as a sequential test may reduce the frequency of initial prostate biopsies that miss cancers treated with active monitoring.