Genetic testing for breast and ovarian cancer
Published on September 26, 2011 at 3:05 AM
By Dr Ananya Mandal, MD
September is Ovarian Cancer Awareness month and next month starts Breast Cancer Awareness month. Genetic testing is emerging as a popular method to pinpoint those at risk.
Experts from Cancer Treatment Centers of America (CTCA) provide some clues as to who should be using these tests. They explain that women who have been diagnosed with cancer and/or people who have a strong family history of cancer can consider genetic testing. Red flags to consider are anyone in the family who developed cancer at a young age, multiple family members who developed cancer, if a person experienced bilateral cancer (cancer in both breasts), breast and ovarian cancer in the same woman, or cancer appeared where it wasn’t expected (like breast cancer in men)
New National Comprehensive Cancer Network (NCCN) guidelines suggest BRCA (BRCA1 and BRCA2 are human genes that belong to a class of genes known as tumor suppressors) testing for any woman who has been diagnosed with ovarian cancer and for any woman who has been diagnosed with any type of breast cancer at age 45 or younger or with triple negative breast cancer at age 60 or younger.
All persons undergoing genetic testing need to be counseled said CTCA. Melanie Corbman says “I talk to the patients about their cancer history and the history of cancer in the family to decide whether it looks like the cancer in the family is something that is hereditary. I explain genetic testing and how it can be helpful for the patient and their family members”. Corbman says to “get the best answers from genetic testing if we do the testing in someone who already has been diagnosed with cancer.”
The CTCA explains that genetic testing involves a simple blood or saliva test that is then sent to a lab that does the genetic testing.
Breast cancer is common in the general population. The average woman’s risk for breast cancer is about 12% but a woman with a BRCA mutation can have up to an 85% risk of developing breast cancer. A woman who has already been diagnosed with breast cancer and who has BRCA mutation has a higher risk of getting a new breast cancer. The average woman’s risk of getting ovarian cancer is low, about 1.5% but a woman with a BRCA mutation can have up to a 50% risk of getting ovarian cancer. Women with a cancer diagnosis may want to be more aggressive with their treatment if they know they have a BRCA mutation and have a higher chance of getting cancer again.
Men who test positive for the BRCA gene mutations have a slightly increased risk of breast cancer and about a 25%, increased risk for prostate cancers. These men should start screening for prostate cancer at age 40. Both men and women who have a history of pancreatic cancer in their families and have tested positive for a BRCA2 mutation may have an increased risk.