Researchers have developed a test that can spot the recurrence of prostate cancer earlier than conventional tests, which could allow physicians to identify warning signs that the disease may return following prostate surgery. Chad Mirkin and colleagues used gold nanoparticles to detect prostate specific antigen (PSA), a marker of prostate cancer found in the blood, in 18 men. The researchers found that the test is nearly 300 times more sensitive than current commercially available assays. With their measurement technique, low levels of PSA, which would likely have been missed using existing measures, could be detected in samples from every patient following surgery, according to the authors. In some samples, the authors associated a rise in the patient's PSA levels and a recurrence of the cancer, whereas in others, low levels of PSA were connected with the cancer's non-recurrence. The researchers suggest that their test may be able to help physicians determine which prostate cancer patients are likely to stay cancer-free after surgery and which are relapsing. The method may also help monitor the effectiveness of post-surgery therapies such as chemo- or radiation therapy, according to the authors.

Source: Proceedings of the National Academy of Sciences

Article: "The nanoparticle-based bio-barcode assay redefines 'undetectable' PSA and biochemical recurrence following radical prostatectomy," by C. Shad Thaxton, Robert Elghanian, Audrey D. Thomas, Savka I. Stoeva, Jae-Seung Lee, Norm D. Smith, Anthony J. Schaeffer, Helmut Klocker, Wolfgang Horninger, Georg Bartsch, and Chad A. Mirkin