Prostate cancer is common, especially in developed regions such as the USA and Europe. But many cases of prostate cancer are incidental, and would never have caused a problem had we not found them. To help determine who is a candidate for active surveillance, and who might be best served with intervention such as surgery or radiation therapy, we historically have used measures of PSA, grade, stage, and life expectancy. Now, there are at least a dozen different genetic tests for prostate cancer under development.
What: There are 2 tests currently available: Oncotype DC (Genomic Health, Redwood City, California) and Prolaris (myriad Genetic Laboratories, Sale Lake City). Both tests can identify which low-risk patients are “truly” at low risk, and can be managed by active surveillance (rather than immediate treatment). Today, I will focus on the OncoType DX test.
The OncoType DX prostate cancer assay was recently launched. The test is based on a biopsy specimen from your prostate, and creates an assay of the levels of expression of 17 genes that can predict the aggressiveness of the cancer. A genomic score is generated, ranging from 0 to 100 to determine the level of risk. A clinical validation study showed OncoType DX to significantly predict the aggressiveness of disease beyond clinical factors such as PSA and Gleason score. The percentage of patients having very low risk disease went from 5% to 10% based on PSA level and Gleason score to 26% when the genomic predictor score was factored into the assessment. On the other hand, 10% of patients thought to be at low or very low risk were identified as having more aggressive disease by the Oncotype DX testing.
The test costs about US$3,800. Genomic Health is presenting evidence to insurers in an attempt to get coverage of the test.
My take: Prostate cancer is a very heterogeneous disease. Tests such as these may move us closer to personalized management, and I think that these tests hold great promise. We really need to know which group of men with Gleason score 6 should not be managed by active surveillance. I’m Dr. Michael Hunter.
The small print: The material presented herein is informational only, and is not designed to provide specific guidance for an individual. Please check with a valued health care provider with any questions or concerns. As for me, I am a Harvard- , Yale- and UPenn-educated radiation oncologist, and I practice in the Seattle, WA (USA) area. I feel genuinely privileged to be able to share with you. If you enjoyed today’s offering, please consider clicking the follow button at the bottom of this page.
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