Saturday 22 September 2018 1:47 AM UTC
WASHINGTON Sept 22: Eight out of every 10 people that have genes that raise their risks for breast, pancreatic, ovarian and prostate cancers do not know it, a new study reveals.
Mutations of the BRCA1 and BRCA2 genes raise a woman’s risk of developing breast cancer before the age of 80 by 72 percent and 69 percent.
On the same genes, mutations also increase pancreatic cancer for people of any gender, of ovarian cancer for women and prostate cancer for men.
Despite the fact that genetic testing offer a likely opportunity to predict a BRCA-related cancer, most people rely on their relatives to tell them if they have a family history of risk.
The authors of a new study from Yale University are urging people to get tested for the gene variations after discovering that only 18 percent of people they tested knew their DNA was dangerous.
It was discovered in the mid-1990s that mutations on the BRCA1 and BRCA2 raised breast cancer risks for women.
Since then, we have learned that various mutations on those same genes can similarly affect the risks of ovarian, prostate and pancreatic cancers, as well as breast cancer for men.
In part because it is so common, the US government and institutions the world over have thrown their weight into breast cancer research.
One in every eight women in the US will develop breast cancer at some point in their lives.
Collectively, nearly 406,000 Americans are diagnosed pancreatic, prostate or ovarian cancer.
An international dedication to finding a cure have driven death rates for breast cancer down significantly.
But even in this age of curable breast cancer,more than 40,000 American women are expected to die of breast cancer this year alone.
As with any cancer, the best ‘treatment’ is prevention, and second to that is early detection.
A simple blood or saliva test at any age – even in infancy – can detect BRCA mutations.
After the discovery of the two BRCA genes in the 1990s, there was a surge in women getting their DNA tested.
But then an odd thing happened, beginning in 2004: there was a sharp increase in the number of low-risk (with no or a minimal family history of breast cancer).
Meanwhile, many women with significant family histories of breast cancer were not getting tested.
The new study, published in JAMA Network Open, suggests that something similar is still going on.
When the authors screened the genomes of over 50,000 men and women, they found that 267 had one of the BRCA mutations that put them at risk for cancer.
Only 18 percent of those who had cancer-related mutations were aware of their risks.
In fact, between their new research and their previous related study, the Yale University research has been responsible for the discovery of cancer for four participants.
‘Three of these cases were people who wouldn’t meet the screening criteria. Like a lot of people, they had no family or personal history that suggested they would have this,’ senior study author Dr Michael Murray told Daily Mail Online.
Genetic screening is typically only recommended for people who have a ‘significant’ family and/or personal history of cancers that could be related to BRCA mutations.
The concern is that testing people at low risk will cause undue worry.
But Dr Murray suggests that precaution has perhaps been taken too far.
‘With the change in cost and the improved ability to interpret the data I think we should be thinking about when and if and how to use genomic screening,’ he said.
In 2015, Dr Murray says that BRCA testing would have cost about $3,000. Now, he estimates getting screened is about ‘a tenth’ of that price.
Direct-to-consumer genetic tests like 23andMe, which costs as little as $150, include BRCA testing, but it ‘offers testing for just three variants in the two genes,’ explains Dr Murray.
‘That’s only a tiny sliver of a window of the risks.’
Doctors may fail to recommend BRCA screening to their patients simply because they don’t take a complete family and personal medical history.
Doing so would take 15 to 20 minutes, ‘a long time,’ for doctors, Dr Murray says.
And family history alone ‘doesn’t work for analyzing every risk variant,’ and nor does testing alone.
Dr Murray hopes that the knowledge that more than 80 percent of people walking around with dangerous genes will encourage more patients to discuss their full histories and splash out for genetic testing.
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