TAMPA — Ovarian cancer has long been called the "silent killer," its symptoms going unnoticed until the disease is so advanced it is all but untreatable.
But what if doctors could predict which women are at highest risk for the cancer — and why?
Moffitt Cancer Center researchers have helped identify four DNA hotspots associated with higher risk of developing the fifth-deadliest cancer among women. Two large studies compared the genetic material of more than 18,000 women who had ovarian cancer with that of 26,000 healthy women.
Mutations in the so-called BRCA genes were identified years ago as a high genetic risk factor for breast and ovarian cancers. By zeroing in on new regions of the genome, the Moffitt studies indicate there are other genes or other mechanisms that might contribute to ovarian cancer, said Tom Sellers, Moffitt director and a senior author on the two new studies.
While the findings are not yet ready for clinical use, they are another step toward creating a genetic test to identify women with higher-than-average risk for ovarian cancer.
"It's very early in the game still, but I think it's inevitable" that such a test will be developed, Sellers said.
What if women knew from genetic testing they stood a strong chance of developing ovarian cancer? Sellers said they could not only make sure their doctors monitor them for the earliest signs of disease, they also could take steps to help prevent it.
"Ovarian cancer is one of the malignancies for which we can greatly lower risk," he said.
Using oral contraception reduces ovarian cancer risk, for instance, Sellers said. Women in the highest-risk categories may also consider having their fallopian tubes tied or even their ovaries removed before disease begins, he said.
The Moffitt studies are part of a massive international investigation into the genetic basis of hormone-related cancers, including those of the ovaries, breast and prostate. That project, known as the Collaborative Oncological Gene-environment Study, nearly doubled the number of genetic signposts known to be linked with these cancers.
The project resulted in a coordinated series of 13 publications in scientific journals late last month. Most of the research was financed by the European Union, the U.S. National Institutes of Health and Cancer Research U.K.
Moffitt joined that work due to Seller's ongoing affiliation with the Ovarian Cancer Association Consortium.
Each year, about 20,000 women in the United States are diagnosed with ovarian cancer, according to the Centers for Disease Control and Prevention.
The five-year survival rate is over 90 percent if the disease is caught in the early stages, according to the National Ovarian Cancer Coalition. But due to ovarian cancer's vague symptoms and the lack of early detection tests, less than 20 percent of all cases are found at this early stage.
Knowing one's genetic history doesn't necessarily make medical decisions easy. Consider women who test positive for changes in the BRCA gene mutations. They face any number of difficult choices — from intensive monitoring to preventive mastectomies or removal of healthy ovaries. Not even doctors agree on the best approach.
But one breast cancer study that was part of the international project suggests researchers may one day be better able to better guide women with the BRCA mutation by separating those at the highest cancer risk (more than 80 percent) from those with lower risks.
The more specific information patients can get, the better decisions they can make, Sellers said.
"We're getting to the point where one could draw a sample of DNA at birth and sequence it and put it on a credit card and keep it and that's part of your medical record," he said. "And if we were smart enough about how we use genetic information, it really could inform lifetime risks."
Information from the Associated Press was used in this report. Jodie Tillman can be reached at firstname.lastname@example.org or (813) 226-3374.