Single Molecule Array Predicts Survival After Prostatectomy

A fifth-generation digital immunoassay is a reliable predictor of five-year biochemical recurrence (BCR)-free survival following radical prostatectomy (RP).

The immunoassay uses Single Molecule Array (SiMoA) technology based upon the isolation of individual immunocomplexes on beads using standard enzyme linked immunosorbent assay (ELISA) reagents.

Scientists utilized frozen serum specimens, provided by the Langone Medical Center (New York University, NY, USA), and the Johns Hopkins University School of Medicine (Baltimore, MD, USA), from men who had undergone RP and who had no evidence of BCR using conventional Prostate Specific Antigen (PSA) measurement methods.

The Quanterix AccuPSA assay (Quanterix Corporation, Cambridge, MA, USA), was capable of accurately measuring PSA levels in all men following surgery. The Quanterix assay has an analytical sensitivity 1,000-fold lower than conventional ultra sensitive PSA assays. AccuPSA nadir levels were significantly different between the non-BCR group whose mean was 2.27 pg/mL and the BCR group whose mean was 46.99 pg/mL. A Kaplan-Meir analysis demonstrated for the five years follow-up, 100% of men with AccuPSA nadir values of less than 3 pg/mL did not develop BCR, whereas 62.5% of men with values greater than 3 pg/mL developed BCR. The sensitivity, specificity, positive predictive value and negative predictive value of the AccuPSA test was 100%, 75%, 69% and 100% respectively.

Herbert Lepor, MD, a prostate cancer expert at NYU, said, "These results have important implications for the way prostatectomy patients will be managed in the future. Not only will physicians be able to reassure patients who are at low risk of recurrence following radical prostatectomy, but the identification of a reliable predictor of recurrence soon after surgery has important implications for the frequency of PSA testing and selection of candidates for adjuvant therapy. In addition to providing patients with peace of mind, implementation of this test could lead to a reduction in healthcare costs.” The study was published online on October 12, 2011, in the British Journal of Urology International.


Related Links:
New York University Langone Medical Center
Johns Hopkins University School of Medicine
Quanterix Corporation