Does the Presence of Primary Circulating Prostate Cells Imply the Presence of Agressive Prostate Cancer with Early Biochemical Failure: a Comparison with the Walz Nomogram

Background: To determine the utility of primary circulating prostate cells (CPC) for predicting early biochemical failure after radical prostatectomy for prostate cancer and compare the results with the Walz nomogram. Materials and Methods: A single centre prospective study of men with prostate cancer treated with radical prostatectomy was conducted between 2004 and 2014. Clinicalpathological details were registered, along with total serum PSA presurgery, Gleason score, extracapsular extension, positive surgical margins, infiltration of lymph nodes, seminal vesicles and pathological stage. Primary circulating prostate cells were obtained using differential gel centrifugation and detected using standard immunocytochemistry with antiPSA. Biochemical failure was defined as a PSA >0.2ng/ml, predictive values were calculated using the Walz nomagram and CPC detection. Results: A total of 285 men participated, of whom 103/285 (36.1%) suffered biochemcial failure; 32/103 (31.1%) within two years of radical prostatectomy. Men with higher Gleason scores, higher pathological stage, infiltration of the surgical margin or prostate capsule and infiltration of seminal vesicles were more likely to undergo biochemical failure. There was a significant increase in the frequency of biochemical failure with increasing number of CPCs detected (p<0.0004 Chi squared for trend) and increasing percent prediction for the Walz nomogram (p<0.0001 Chi squared for trends). The positive predictive value of primary CPC detection, even using a cutoff point of 4 cells/sample was very low. Conclusions: The detection of primary CPCs in men as a prognostic factor pretreatment fails to identify those at high risk of biochemical failure within two years of curative therapy. This is in keeping with their biological significance, that the majority of them will be eliminated by the primary therapy and thus have no influence on the subsequent clinical history of the patient.