Primary Circulating Prostate Cells Are Not Detected in Men with Low Grade Small Volume Prostate Cancer

Objective. To determine if primary circulating prostate cells (CPCs) are found in all men with prostate cancer. Methods and Patients. A prospective study, to analyze all men with an elevated PSA between 4.0 and 10.0 ng/mL undergoing initial biopsy. Primary CPCs were obtained by differential gel centrifugation and detected using standard immunocytochemistry using anti-PSA; positive samples underwent a second process with anti-P504S. A malignant primary CPC was defined as PSA (+) P504S (+) and a test positive if 1 cell/4 mL was detected. Biopsy results were registered as cancer/no-cancer, number of cores positive, and percent infiltration of the cores. Results. 328/1123 (29.2%) of the study population had prostate cancer diagnosed on initial biopsy, and 42/328 (12.8%) were negative for primary CPCs. CPC negative men were significantly older, and had lower PSA levels, lower Gleason scores, and fewer positive cores and with infiltration by the cancer. 38/42 (91%) of CPC negative men complied with the criteria for active surveillance in comparison with 34/286 (12%) of CPC positive men. Conclusions. Using primary CPC detection as a sequential test to select men with an elevated PSA for biopsy, the risk of missing clinically significant prostate cancer is minimal when the patient is primary CPC negative; less than 0.5% of all primary CPC negative men had a clinically significant prostate cancer.