Gene test may cut need for prostate cancer surgery
LONDON (Reuters) - A genetic pattern could predict how aggressive prostate cancer is, potentially saving many men with less threatening tumors from undergoing unnecessary and life changing surgery, scientists said on Wednesday.
Prostate tumors can range from relatively harmless ones that grow very slowly and are unlikely ever to cause a problem, to ones that are far more aggressive and need swift treatment. At present doctors have few effective tools to differentiate between varying types.
British researchers found that men with the highest levels of "cell cycle progression" (CCP) genes -- ones that encourage cells to grow -- were three times more likely than those with the lowest levels to have a fatal form of prostate cancer.
The study, published in the Lancet Oncology journal, also found that in patients who had already had surgery to remove their prostate, those with the highest CCP levels were 70 percent more likely to have a recurrence of the disease.
"Our findings have great potential," said Jack Cuzick, a cancer specialist based at Queen Mary, University of London.
"CCP genes are expressed at higher levels in actively growing cells, so we could be indirectly measuring the growth rate and inherent aggressiveness of the tumor through a test."
Myriad Genetics in the United States, has developed a test called Prolaris which measures CCP levels and Cuzick said that if further trials confirm his results, doctors could be using it in prostate cancer patients within a year.
Prostate cancer killed an estimated 258,000 men around the world in 2008 and is the second most common cause of cancer death in men in the United States. In Britain, about 35,000 men are diagnosed with it and some 10,000 die from the disease each year.
Being able to distinguish between aggressive tumors and slow-growing ones could spare many men unnecessary treatment and side effects like impotence and incontinence.
The study looked at 703 men with prostate cancer -- 366 men in America who had undergone surgery to remove the prostate, and 337 men in Britain with cancer that was confined to the prostate and were judged to not need immediate treatment.
The untreated group were given what is called a "watch and wait" option, which allows doctors to try to avoid treating men whose prostate cancer will not cause them significant problems. Tissue samples from the prostate were either taken during surgery or from the biopsy used to diagnose the disease.
Researchers then tested each sample for levels of 31 different genes involved in CCP and were able to show that specific combination of these gene levels can identify men at high or low risk of the disease spreading beyond the prostate and those most likely to die.
Cuzick said previous studies had already shown that CCP levels can predict survival for breast, brain and lung cancers.
Helen Rippon, head of research management, at the British Prostate Cancer Charity, said in a statement the technology must be "comprehensively trialed in large numbers of men before it can be introduced into routine clinical practice."
(Editing by Matthew Jones)
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