Prostate cancer recurrence detected earlier

A novel technology using gold nanoparticles might predict the recurrence of prostate cancer earlier than current blood tests, a pilot study found.

In an 18-patient study, Nanosphere Inc.'s new method detected a protein specific to prostate cancer in 86 percent of blood samples compared with 25 percent for conventional tests, according to research published online in the Proceedings of the National Academy of Sciences. The company attaches antibodies to the gold, producing what Nanosphere calls probes for "ultrasensitive" detection of proteins that may otherwise go undiscovered.

About 70,000 men a year undergo surgery to remove diseased prostates and 40 percent will have their cancer return, according to C. Shad Thaxton, the lead author. If the test works in larger studies, doctors may be able to diagnose recurrence of the disease several years earlier than what now is the norm, the researchers said.

"It gives them a whole new tool to help people who have just undergone radical surgery for a potentially lethal disease," Chad Mirkin, a study author and a professor of chemistry at Northwestern University in Evanston said. "It gives them the ability to figure out if the patient is in good shape sooner than the commercial tools do, so you can take the weight of the world off their shoulders."

The new test, developed by Northwestern and licensed by Northbrook-based Nanosphere, finds previously undetectable levels of a protein in the blood called prostate-specific antigen, or PSA, a marker to determine cancer. After surgery to remove the prostate gland, patients typically have PSA levels too low to be seen using conventional tests.