Comparison of the Walz Nomogram and Presence of Secondary Circulating Prostate Cells for Predicting Early Biochemical Failure after Radical Prostatectomy for Prostate Cancer in Chilean Men

Purpose: To determine the utility of secondary circulating prostate cells for predicting early biochemicalfailure after radical prostatectomy for prostate cancer and compare the results with the Walz nomagram.Materials and
Methods: A single centre, prospective study of men with prostate cancer treated with radicalprostatectomy between 2004 and 2014 was conducted, with registration of clinical-pathological details, total serumPSA pre-surgery, Gleason score, extracapsular extension, positive surgical margins, infiltration of lymph nodes,seminal vesicles and pathological stage. Secondary circulating prostate cells were obtained using differentialgel centrifugation and assessed using standard immunocytochemistry with anti-PSA. Biochemical failure wasdefined as a PSA >0.2ng/ml, predictive values werecalculated using the Walz nomagram and CPC detection.
Results: A total of 326 men participated, with a median follow up of 5 years; 64 had biochemical failure withintwo years. Extracapsular extension, positive surgical margins, pathological stage, Gleason score ≥ 8, infiltration ofseminal vesicles and lymph nodes were all associated with higher risk of biochemical failure. The discriminativevalue for the nomogram and circulating prostate cells was high (AUC >0.80), predictive values were higher forcirculating prostate cell detection, with a negative predictive value of 99%, sensitivity of 96% and specificity of75%.
Conclusions: The nomagram had good predictive power to identify men with a high risk of biochemicalfailure within two years. The presence of circulating prostate cells had the same predictive power, with a highersensitivity and negative predictive value. The presence of secondary circulating prostate cells identifies a groupof men with a high risk of early biochemical failure. Those negative for secondary CPCs have a very low risk ofearly biochemical failure.