Test Determines Whether Prostate Cancer Returns After Surgery

An ultrasensitive prostate-specific antigen (PSA) test using nanoparticle-based technology may be able to predict definitively if the cancer is cured after surgery or if it will recur.

In a man who has his cancerous prostate removed, there should be no PSA in the blood except for a minute amount produced by the periurethral glands. However, any PSA produced by cancer recurrence ends up in the blood stream, and can be detected earlier with the more sensitive nanotechnology PSA assay.

The new test is 300 times more sensitive than currently available commercial tests and can detect a very low level of PSA that indicates the cancer has spread beyond the prostate. The test also may pick up cancer recurrence at a much earlier stage, when secondary treatment is most effective for a patient's survival. Current tests that measure the level of protein called PSA, which signals the presence of cancer, may detect no PSA, only to have cancer return in up to 40 % of the cases.

In addition to more accurately predicting the course of the disease, the new test gives an early indication of whether secondary treatments, such as radiation and hormone therapy, are working. If not, doctors can quickly begin alternative treatment and refer patients to clinical trials.

Scientists at Northwestern University Feinberg School of Medicine (Chicago, IL, USA) and the University International Institute for Nanotechnology (Evanston, IL, USA) are developing the VeriSens PSA test using nanoparticle-based technology from Nanosphere, Inc. (Northbrook, IL, USA). Their aim is to predict definitively after surgery if the cancer is cured long term or if it will recur.

As result of the study, the scientists were able to assign a PSA level number to a cure for the first time as well as a number that indicated the disease would recur and if it would recur aggressively. These newly identified levels were below what could have been detected with the conventional PSA test. Quantification of PSA values was possible at less than the clinical limit of detection for commercial assays.

The next step is a prospective clinical trial to compare the nanoparticle-enhanced PSA assay to traditional PSA assays and determine if earlier detection and treatment can save lives.

Related Links:
Northwestern University Feinberg School of Medicine
International Institute for Nanotechnology
Nanosphere, Inc.