A new genetic test to gauge the aggressiveness of prostate cancer may help tens of thousands of men each year decide whether they need to treat it right away or can safely monitor it.
The new test, which goes on sale today, joins another one that recently came on the market. Both analyze multiple genes in a biopsy sample and give a score for aggressiveness, similar to tests used now for certain breast and colon cancers.
Doctors say tests such as these have the potential to curb a major problem in cancer care: overtreatment. Prostate tumors usually grow so slowly that they'll never threaten a man's life, but some prove fatal, and there's no reliable way now to tell which ones. Treatment with surgery, radiation or hormone blockers isn't needed in most cases and can cause impotence or incontinence, yet most men fear skipping it.
"You can shop for a toaster" better than for prostate treatment, said Peter Carroll, chairman of urology at the University of California, San Francisco. A study he led of the newest test, the Oncotype DX Genomic Prostate Score, is set for discussion today at an American Urological Association meeting in San Diego.
The results suggest the test could triple the number of men thought to be at such low risk for aggressive disease that monitoring is a clearly safe option. Conversely, the test also suggested that some tumors were more aggressive than doctors thought.
Independent experts say such a test is desperately needed, but it's unclear how much data this one adds or whether it will be enough to persuade men with low-risk tumors to forgo treatment, and treat it only if it gets worse. Only 10 percent who are candidates for monitoring choose it now.
The company will charge $3,820 for the prostate test.