Background The low specificity of serum PSA resulting in the inability to effectively differentiate prostate cancer from benign prostate conditions is a persistent clinical challenge. The low sensitivity of serum PSA results in false negatives and can miss high‐grade prostate cancers. We describe a non‐invasive test for detection of prostate cancer based on functional enrichment of prostate adenocarcinoma associated circulating tumor cells (PrAD‐CTCs) from blood samples followed by their identification by immunostaining for pan‐cytokeratins (PanCK), prostate specific membrane antigen (PSMA), alpha methyl‐acyl coenzyme‐A racemase (AMACR), epithelial cell adhesion molecule (EpCAM), and common leucocyte antigen (CD45). Methods Analytical validation studies were performed to establish the performance characteristics of the test using VCaP prostate cancer cells spiked into healthy donor blood (HDB). The clinical performance characteristics of the test were evaluated in a case–control study with 160 known prostate cancer cases and 800 healthy males, followed by a prospective clinical study of 210 suspected cases of prostate cancer. Results Analytical validation established analyte stability as well as acceptable performance characteristics. The test showed 100% specificity and 100% sensitivity to differentiate prostate cancer cases from healthy individuals in the case control study and 91.2% sensitivity and 100% specificity to differentiate prostate cancers from benign prostate conditions in the prospective clinical study. Conclusions The test accurately detects PrAD‐CTCs with high sensitivity and specificity irrespective of stage, serum PSA or Gleason score, which translates into low risks of false negatives or overdiagnosis. The high accuracy of the test could offer advantages over PSA based prostate cancer detection.

BackgroundEvaluation of serum prostate specific antigen (PSA) is a part of standard prostate cancer diagnostic work-up in symptomatic males as well as for elective prostate cancer screening in asymptomatic males. The low specificity of serum PSA leading to an inability to effectively differentiate prostate cancer from benign prostate conditions is a persistent clinical challenge. Further, the low sensitivity of serum PSA leading to false negatives can miss high-grade / aggressive prostate cancers.ObjectiveWe describe a non-invasive prostate cancer detection test based on functional enrichment of prostate adenocarcinoma associated circulating tumor cells (PrAD-CTCs) from blood samples and their identification via immunostaining for pan-cytokeratins (PanCK), prostate specific membrane antigen (PSMA), alpha methyl-acyl coenzyme-A racemase (AMACR), epithelial cell adhesion molecule (EpCAM) and common leucocyte antigen (CD45).Design, Setting, and ParticipantsThe analytical validation studies used VCaP reference prostate cancer cell line to evaluate the performance characteristics of the test. The clinical performance characteristics of the test were first evaluated in a case-control study with 160 known prostate cancer cases and 800 healthy males. A prospective clinical study was performed with samples from 210 suspected cases of prostate cancer.Outcome Measurements and Statistical AnalysisAnalytical validation established analyte stability as well as acceptable performance characteristics. The test showed 100% specificity and 100% sensitivity to differentiate prostate cancer cases from healthy individuals in the case control study and 91.2% sensitivity and 100% specificity to differentiate prostate cancers from benign prostate conditions in the prospective clinical study.Results and LimitationsThe test accurately detects PrAD-CTCs with high sensitivity and specificity irrespective of stage or grade (Gleason score), which translates into low risks of false negatives or overdiagnosis. The test does not detect minor non-adenocarcinoma subtypes of prostate cancer.ConclusionsThe high accuracy of the test offers advantages over PSA based prostate cancer detection.