Using PET scans, US researchers successfully pinpoint and track prostate cancer cells as they spread to the lymph nodes in mice, a method they believe has the potential to improve the way advanced prostate cancer is treated in men.

The findings by Lily Wu, a researcher at University of California, Los Angeles, were published in the latest edition of the journal Nature Medicine.

Wu and her research team engineered a common cold virus to travel to the lymph nodes, using a prostate cancer-specific vector that dictates its payload be expressed only in prostate cells. The payload in this case is a protein that can be imaged by Positron Emission Tomography (PET) scanning.

The virus was introduced into the tumor in the mouse and scientists were able to detect PET signals only from the lymph nodes with cancer cell involvement, indicating the virus reached and infected the prostate cancer cells and produced the imaging protein.

This discovery could aid oncologists in finding the cancer's spread earlier when it's more treatable and before it invades distant organs, Wu said in a release.

"We now know we can reach these prostate cancer metastases at an earlier stage than before, and we know we can deliver genes to those cancer cells that produce proteins that can be imaged by PET," Wu said. "Now we will find out how effective this genetic toxic payload is in preventing further spread of the cancer to other vital organs."

Wu said this type of image-guided therapy has the potential to improve the way advanced prostate cancer is treated.

"It would represent a treatment advance in patients for whom outcome is not good," Wu said. "This would help improve the prognosis for these patients by letting us find and treat these metastases early. If we can catch the cancer before it invades other organs, we have a better chance to change the outcomes for these patients."

(Xinhua News Agency July 14, 2008)