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 their cancer 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 like these have the potential to curb a major problem in cancer care - overtreatment. Prostate tumors usually grow so slowly they will never threaten a man's life, but some prove fatal and there is no reliable way now to tell which ones will. Treatment with surgery, radiation or hormone blockers isn't needed in most cases and can cause impotence or incontinence, yet most men are afraid to skip it.
"We're not giving patients enough information to make their decision," said Dr. Peter Carroll, chairman of urology at the University of California, San Francisco. "You can shop for a toaster" better than for prostate treatment, he said.
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 some tumors were more aggressive than doctors had believed.
The newest test was developed by Genomic Health Inc., which has sold a similar one for breast cancer since 2004. Doctors at first were leery of it until studies in more groups of women proved its value, and the same may happen with the prostate test, said Dr. Len Lichtenfeld, the American Cancer Society's deputy chief medical officer.
The company will charge $3,820 for the prostate test and says it can save money by avoiding costlier, unnecessary treatment. Another test for assessing prostate cancer risk that came out last summer -Prolaris by Myriad Genetics Inc. -sells for $3,400.
About 240,000 men in the U.S. are diagnosed with prostate cancer each year, and about half are classified as low risk using current methods. Doctors now base risk estimates on factors such as a man's age and how aggressive cells look from biopsies that give 12 to 14 tissue samples. But tumors often are spread out and vary from one spot to the other.