Gene Test Shows Promise for Identifying Aggressive Prostate CancerSep 19, 2013
Researchers from Columbia University have identified 3 genes they used to predict whether prostate cancer in men with low-risk disease would stay low-risk, or become more of a threat. Researchers are looking for ways to accurately determine whether men’s prostate cancer will grow slowly or quickly, in order to help them decide how best to treat it. The study was published online September 11, 2013 in Science Translational Medicine.
“Currently there are now many men diagnosed with prostate cancer very early in the course of the disease, partly due to increased awareness and partly due to increased screening, said American Cancer Society Professor and co-senior author, Cory Abate-Shen, PhD. “Many of them have lesions which are never going to manifest as harmful. The problem we started with was how to distinguish between early lesions that were or were not going to become harmful tumors.”
The researchers analyzed prostate biopsy specimens from 43 men who were followed for at least 10 years through active surveillance (with no immediate treatment). All the men had been diagnosed with low-risk prostate cancer, but in 14 of them the cancer eventually started to grow or become more aggressive. All 14 were correctly identified by the gene test.
The 3 genes the researchers tested for were associated with aging in a way that suppressed the growth of tumors. In the study, men whose tumors had higher levels of those genetic biomarkers were less likely to have their prostate cancer grow or become more aggressive.
Abate-Shen said even though the data is strong, much larger studies are needed to validate the results before the test can be made available to patients and doctors. Her team is working on one such study now, and is setting up a broader trial that will take even more time and resources.
Treatment decisions remain complicated
For now, deciding how (or whether) to treat low-risk prostate cancer is still complicated. Prostate cancer is often found early using a PSA blood test and a digital rectal exam (DRE). If those tests raise concerns, the patient may undergo a biopsy that examines prostate tissue. If cancer cells are detected, the cancer is given a Gleason score from 2 to 10 based on how the cells look under a microscope. A score of 6 or lower is considered to be low-risk. But these tests are not perfect. Some prostate cancers grow slowly and may never cause a man any problems (and therefore might not need to be treated), while others are more aggressive. The tests don’t always accurately predict which cancers are which.
How actively to treat prostate cancer that was caught early is a very personal decision. Options might include just carefully monitoring the cancer to see if it grows, or treating it with surgery or radiation. Some men may be more concerned about removing or destroying the cancer, while other men may be more concerned about avoiding or delaying possible side effects from treatment such as incontinence and impotence. It’s important for men considering prostate cancer treatment to be fully informed about all their options and to have an open, honest discussion with their doctor.
A Molecular Signature Predictive of Indolent Prostate Cancer. Published online September 11, 2013 in Science Translational Medicine. First author Shazia Irshad, Columbia University, New York.