Genetic Risk, Fine-Tuned: Researchers Offer New Data
Step by step by step, researchers are making progress towards cancer becoming a treatable condition – rather than a death sentence.
What’s your risk of breast cancer – really?
Sure, most of us know our lifetime risk of being diagnosed with breast cancer is about 12%. One in 8 American women will experience breast cancer by the time they die.
But that’s lifetime risk – risk calculated over the entire 80 to 90 to 100 years you’re alive. And it will never translate to a risk of 1 in 8 right now, this second. If you’re 20 years old, your risk of being diagnosed with breast cancer by the time you’re 30 is 1 in 1,681. If you’re 70, your risk of being diagnosed by the time you’re 80 is 1 in 27.
Suddenly, that 1 in 8 risk looks a lot less scary.
In addition, as scientists and researchers are continually discovering, there are many factors that can affect that risk.
Think of it this way. The overall risk for Americans of being killed in a car accident is about 1 in 100. But the risk of dying on the highway for someone making a 2-hour commute to work every day is, in reality, higher than that of a nursing home resident who never goes out.
And the breast cancer risk for a 50-year-old woman who’s obese, who smokes, who drinks excessively, and whose mother died of breast cancer is considerably higher than that of a woman in her 20s, living a healthy lifestyle, with no family history of breast cancer.
It behooves all of us to get beyond that 1-in-8 figure, and try to assess our own personal risk of breast cancer. And in the future, figuring that personal risk may very well include evaluating data right down to the cellular level: our own genomic profiles, e.g., our personal genetics.
A massive study involving over 130 institutions spread throughout the world, and 200,000 study subjects, has just brought the future one step closer.
The COGS study, released March 27, 2013, was spearheaded by Cancer Research U.K., in conjunction with both the European Union and America’s National Institutes of Health. The data collected doubles the number of known risk markers – genetic aberrations – for three common cancers: breast, ovarian, and prostate.
In addition, these new markers tell scientists more about the “biological underpinnings” of these three cancers – which can help lead to better, more targeted treatments in the future. (Ritter, 2013)
Doctors have known for quite some time that certain aberrations in the BRCA1 and BRCA2 genes significantly increase a woman’s risk of breast cancer. But is every woman with these gene mutations – estimated to be slightly less than 1% of the overall population – at the same risk for developing breast cancer?
By increasing the pool of risk markers that might point to cancer, researchers are coming closer to being able to determine which women with BRCA aberrations are at high risk – 80% or higher – of developing breast cancer; and which are at lower risk – perhaps as low as 20%.
This kind of risk-factor fine-tuning could result in women at high risk considering an immediate mastectomy/hysterectomy; while those at lower risk might feel comfortable waiting awhile and starting a family, rather than having life-altering surgery in their 20s or 30s.
This new research makes it possible, the study authors say, for scientists to identify women who are at twice the average risk for breast cancer: estimated to be about 5% of all women in developed countries. In addition, about 1% of women are three times more likely to get breast cancer than the general population; and these new markers allow scientists to identify that group, as well.
Hilary Burton, director of the PHG Foundation – a genomics think-tank in Cambridge, England – says that the fine-tuning of personal risk factors made possible by this newest data may soon reduce the number of screening mammograms performed each year by about 20%. (Ritter, 2012)
So what does this mean for you?
If you already know you’re at high risk due to BRCA mutation and/or a strong family history of breast cancer, you might ask your doctor about more genetic testing incorporating these new markers.
But if you’re like most of us, the 85% of American women with no known breast-cancer risk factors, the COGS study is simply interesting: no action required. Your risk is small enough that the additional information offered by these new markers won’t impact how you check yourself for breast cancer: via an awareness of how your breasts feel, and by regular mammograms for older women.
More data is needed; scientists estimate they’ve now discovered about 1/3 of the genes affecting breast cancer risk. But that’s twice as many as they knew about a year ago. And eventually, through continued research, we should each be able to determine our exact risk of ever having breast cancer.
Goodbye, generic 1 in 8.
Brown, E. (2013, March 27). Scientists discover new DNA regions associated with three cancers. Retrieved from http://www.latimes.com/news/science/la-sci-cancer-genes-20130328,0,2782430.story
Ritter, M. (2013, March 27). Scientists find new gene markers for cancer risk. Retrieved from http://abcnews.go.com/Health/wireStory/scientists-find-gene-markers-cancer-risk-18822836