WebMD Medical News
Laura J. Martin, MD
Feb. 17, 2011 (Orlando, Fla.) -- Researchers are a step closer to developing a genetic test that could help men with newly diagnosed prostate cancer decide whether they are good candidates for active surveillance or whether they need treatment right away.
"The biggest challenge with newly diagnosed prostate cancer is deciding what to do for men with low-grade, non-aggressive tumors on biopsy," says Eric Klein, MD, chairman of the Glickman Urological and Kidney Institute at Cleveland Clinic.
"Even low-grade tumors have lethal capabilities. So right now, about 90% of men with low-risk cancer choose treatment," typically surgery to remove the prostate or radiation therapy, he tells WebMD.
"There is no question we are overtreating," Klein says.
Many of these men could safely opt for active surveillance, also known as watchful waiting, Klein says. That's because prostate cancer often grows so slowly that it may never become life-threatening.
"The problem: Right now, we have no way to distinguish between non-aggressive cancers and cancers that are so aggressive that they require immediate treatment," he says.
Enter the new test, which characterizes tumors by their genetic fingerprint. It's another version of the OncoType DX test that is used to guide the treatment of some breast cancers and the determine risk of recurrence in some colon cancers.
In a new study, Klein and colleagues analyzed tissue samples from 431 prostate tumors that had been surgically removed from patients treated at the Cleveland Clinic between 1987 and 2004.
"We found a set of about 300 genes that accurately predict whether cancer will come back after surgery," Klein says.
"The genes provide additional information beyond standard clinical and pathological features of the tumor [such as PSA levels and Gleason scores]," he says.
The new test is not ready for prime time yet. But if results of the new study can be replicated, the data will be used to develop a genetic test to distinguish between slow-growing and aggressive cancers, Klein says.
A. Oliver Sartor, MD, medical director of the Tulane Cancer Center in New Orleans, says a lot more work is needed before he would consider using the test.
"I'd want to see the gene expression approach compared to the best available clinical and pathological measures -- PSA levels, Gleason score, etc. -- in order to validate the value of this novel technology," he tells WebMD.
The study was presented at the Genitourinary Cancers Symposium. It was funded by Genomic Health, which makes the other OncoType DX tests.
These findings were presented at a medical conference. They should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.
SOURCES:Genitourinary Cancers Symposium, Orlando, Fla., Feb. 17-19, 2011.Eric Klein, MD, chairman, Glickman Urological and Kidney Institute, Cleveland Clinic.A. Oliver Sartor, MD, medical director, Tulane Cancer Center, New Orleans.
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