A study published in the July issue of the Journal of Clinical Oncology provides new guidelines to help physicians recognize which women should be assessed for hereditary breast and ovarian cancer. Scientists at 12 of the country's leading hereditary cancer centers collaborated with Myriad Genetic Laboratories to examine 238 women diagnosed with breast cancer before age 50 or with ovarian cancer at any age, who had at least one relative with either disease.
Nearly 40% of the participants were found to have abnormalities in either of two genes responsible for most hereditary breast and ovarian cancer, BRCA1 and BRCA2, that led to their cancer.
"This study tells as that all women with breast cancer diagnosed under age 50, and any woman with a history of breast or ovarian cancer in a close relative, should be tested," suggests coauthor Funmi Olopade, M.D., associate professor of medicine and director of the Cancer Risk Clinic at the University of Chicago Medical Center.
"This is important because women and their doctors have struggled with the issue of who should be advised to be tested for hereditary breast and ovarian cancer," said Olopade.
"The data in this study enabled us to create a simple table that indicates a woman's likelihood of having inherited an abnormality in either of the two major breast-ovarian cancer genes, based on her personal and family history of breast and ovarian cancer."
In contrast to previous studies, the study did not find that women of Ashkenazi Jewish ancestry were more likely to carry a mutation in BRCA1 or BRCA2 compared to women of other ethnic backgounds. This is probably because "this the first study to test for BRCA1 and BRCA2 in a large number of women from diverse ethnic backgrounds," explained Olopade.
"Most studies up to now have looked only at BRCA1, and so we've only had half the story," said coauthor Tom Frank M.D. of Myriad Genetic Laboratories. "By looking at the entire sequences of both genes in all of the participants, and comparing the results to their family history, we were able to develop clear guidelines to help physicians identify patients who should be evaluated for hereditary breast and ovarian cancer."
Another of the study's findings suggests that breast cancer survivors should try to find out if they have the hereditary form of the disease; abnormalities in BRCA1 and BRCA2 in women with breast cancer were found to be associated with a 10-fold increase in the risk of developing ovarian cancer.
One of the most important findings of the study, note the authors, was the observation that women with breast cancer who have mutations in either gene have this sharply elevated risk, which was previously associated only with BRCA1.
Most women with breast cancer are not at a significantly increased risk of ovarian cancer, and so the possibility of this disease does not factor into their health care. This study suggests that their doctors should know if a patient has the hereditary form of breast cancer so that her risk of ovarian cancer can be assessed and managed appropriately, with increased surveillance or consideration of prophylactic ovary removal (oopherectomy).
Journal
Journal of Clinical Oncology