In a reversal of current medical thinking, a new Israeli study says that all Jewish Ashkenazi women over 30 should be tested for the BRAC1 and BRAC2 mutations, even if they don’t have a family history of breast or ovarian cancer.
“We should be testing women who are still healthy at a stage when we can prevent the disease,” Dr. Ephrat Levy-Lahad, director of the Fuld Family Department of Genetics at Shaare Zedek Medical Center, said of her findings, which will be published in the Journal Proceedings of the National Academy of Sciences.
Levy-Lahad presented the research at the hospital’s second annual breast cancer symposium, held Sept. 10 at Shaare Zedek in Jerusalem.
The study found that Ashkenazi women who tested positive for the genetic mutations during random screenings had high rates of breast and ovarian cancer, even when they had no family history of the disease. Many of the women identified by the researchers would never have known they were carrying the mutation if not for the screening offered by the study.
The two most common breast cancer genes are BRCA1 and BRCA2. Everyone is born with them, and normally they help protect cells from cancerous changes.
It’s estimated that one in 40 Ashkenazi Jewish women – about 2.3 per cent – carry a BRCA1 or BRCA2 gene mutation, compared to one of every 800 members of the general population, according to the U.S. Centres for Disease Control.
Women carrying a BRCA1 or BRCA2 gene mutation also have a higher than usual risk of developing ovarian cancer. In 1997, researchers at Shaare Zedek, under the guidance of Levy-Lahad, discovered that one-third of the cases of ovarian cancer in Ashkenazi women are due to inherited mutations in the BRCA1 and BRCA2 genes. Since that time, these genes have also been linked to the occurrence of breast cancer.
The new study was done on women of Ashkenazi origin, because in the Ashkenazi population, there are three common mutations that are easy to check at low cost.
To reach random women, 8,000 healthy Ashkenazi men were tested. Of that number, 175 were found to carry the mutation (the gene exists in men but affects almost exclusively women). The women in the families of the carrier men were tested and their family histories were documented. Half of the female carriers had no family history of breast or ovarian cancer.
According to criteria in use today, these women would not have been tested at all, and the gene would have been discovered only after the onset of cancer symptoms. This means that one in every 100 women – one per cent of the population – is not aware she’s a carrier and, therefore, is at risk for breast and ovarian cancer without the ability to take preventive measures.
This significant finding led the researchers to the conclusion that each woman of this group needs to be genetically screened for mutations in the BRCA1 and BRCA2 genes.
Dr. Steven Narod, a world leader in the field of breast and ovarian cancer genetics at the University of Toronto’s affiliated Women’s College Research Institute, has been conducting ongoing testing for BRCA1 and BRCA2.
“We agree with the position that all Ashkenazi Jewish women be tested. It is better to prevent the cancer than treat it,” he said.
But Dr. Robert Nuttall, assistant director of cancer control policy, Canadian Cancer Society, told The CJN that “while genetic screening can identify women at high risk for cancer, there are still questions that need to be addressed before genetic screening is made available to the Ashkenazi Jewish population, or even the general population, regardless of one’s medical history.”
He added: “We need more research about what the best strategy is after the identification of the mutation. These strategies could include counselling, a personal plan of testing, or prophylactic surgery of the breast or ovaries. There may also be psychological or emotional implications that result from an identification of a mutation.”
He said he hopes the Israeli study will encourage more research on BRCA gene mutations in the Ashkenazi population.
“Until then, we encourage people, and especially people of Ashkenazi Jewish ancestry, to be aware of their family history of cancer, and to talk to their doctor about whether they should go for genetic counselling and genetic testing.”