A virus has been linked to the most aggressive form of prostate cancer, potentially leading the way to identifying men with the deadliest tumors and pinpointing their treatment. The discovery, reported today in the Proceedings of the National Academy of Sciences, involves the XMRV virus, discovered just three years ago, said Ila Singh, an associate professor of pathology at the University of Utah in Salt Lake City. Forty-four percent of men with tumors graded 9 out of 10 for severity on a standard scale had evidence of XMRV, Singh’s study found.
More than 190,000 U.S. men will be diagnosed with prostate cancer this year and 27,000 will die, according to the National Cancer Institute. A more accurate way to identify the riskiest cases might improve therapy, since some tumors are slow growing and don’t require aggressive treatment with surgery, chemotherapy or radiation, all of which carry side effects.
“There is a need for a better test to help determine who would benefit from treatment versus who could be left alone,” said Singh, in a Sept. 4 telephone interview. “If this virus turns out to be a cause for a subset of aggressive tumors, then it would be a good test to use and might be better than PSA.” About 1 million men have been needlessly treated for prostate cancer over the past two decades, largely because of greater use of a blood test for the protein called prostate specific antigen, or PSA, at an estimated cost of $40 billion, according to a study reported Aug. 31 in the Journal of the National Cancer Institute.