Based on a rising PSA after treatment, it looks like a man's prostate cancer has come back. Wouldn't it be nice if his doctor could see it — to know where the cancer cells are, to get an idea of what's going on inside him, and what treatment steps, if any, to take next? Right now, we can't do this. But we're getting closer.

“We are in dire need of a way to
detect small lesions—subtle
manifestations of prostate cancer
in men with an elevated PSA,
but no other obvious symptoms."

Looking at images of tissue and trying to pinpoint the prostate cancer cells hasn't worked, says radiologist Martin Pomper, M.D., Ph.D. However, using a contrast chemical that targets something specific to the prostate — a molecule on the surface of prostate cells, for instance — and seeing those tagged cells light up on computer images has great potential. Pomper is leading the first clinical study using positron emission tomography (PET) scans to show probes that are designed to find PMSA, a protein on the surface of the prostate cell membrane. "We are in dire need of a way to detect small lesions — recurrent tumors in the surgical bed, local lymph node invasion, and other subtle manifestations of prostate cancer in men with an elevated PSA, but no other obvious symptoms," he says.

"We have achieved the fundamentals of success with several small molecule, PET-based imaging agents for prostate cancer, and now we intend to bring the best of them to the clinic." Pomper and colleagues are testing the technology on men known to have prostate cancer that is either confined to the prostate, that has come back after surgery in the local area, or that has appeared as distant metastases. If the technology performs as well as Pomper believes it will, he will test it next on men who have a rising PSA after surgery.