If you’re here and reading this, there’s a good chance you know something about BRCA (or alternatively you know me and are here in solidarity. Thanks!). Before last week I knew “something” about BRCA too. But I’m one of those people who find comfort in knowledge and counter anxiety with endless information gathering. So just to get us all (Us all? I might just be talking into the void here) on the same page I’m going to share some BRCA basics.
What is BRCA?
BRCA1 and BRCA2 are genes. Everyone has them. They are “tumor suppressor” genes and most of the time they function to protect people from developing breast and ovarian cancer. BR (breast) + CA (cancer) = BRCA.
What does it mean to have a BRCA mutation?
When someone inherits a mutation, their mutated BRCA gene does not function properly to protect them from cancer. People with a BRCA1 mutation typically have about an 80% chance of developing breast cancer and a 50% chance of developing ovarian cancer during their lifetime. With a BRCA2 mutation the risk is also about 80% for breast cancer and 25% for ovarian cancer. For comparison sake, the general population-based risk rate for breast and ovarian cancer are 12% and 1.5% respectively.
BRCA mutations also carry an increased risk for pancreatic cancer, melanoma, and possibly uterine cancer.
How common are BRCA mutations?
In the general population the rate of BRCA mutation is between 1 in 400 and 1 in 800. So pretty damn rare. It’s much higher (about 1 in 40) in people with Ashkenazi Jewish ancestry (which I do not have). BRCA mutations can be inherited from either your mother or father. There are hundreds of different known BRCA mutations, many of which have been linked back to different ethnic subgroups. For example, the majority of BRCA mutations in Ashkenazi Jewish people are one of three “founder mutations”. There doesn’t seem to be much research or info out there regarding my specific mutation (which is c.1953_1956delGAAA, also know as rs80357526 and 2072del4 in case you were curious).
Do most people with breast/ovarian cancer have BRCA mutations?
Nope. In fact, less than 10% of people with breast cancer and under 20% of people with ovarian cancer have a BRCA mutation. There are other known genetic mutations (like PALB2) that contribute to breast/ovarian cancer risk, and inevitably many more yet to be discovered. However, the vast majority of breast/ovarian cancer cases are not related to a known genetic risk factor.
Who should get tested for BRCA mutations?
Getting tested is a very personal decision best made in collaboration with a doctor and a genetic counselor. However, general guidelines suggest considering testing if you have:
- a personal history of breast cancer (especially early onset) and/or ovarian cancer
- breast cancer in 2+ close relatives on the same side
- a close relative with ovarian cancer
- a close relative with any breast, ovarian, or pancreatic cancer if you are of Ashkenazi Jewish ancestry
- a close relative with a known BRCA mutation
Insurance has a more rigid set of guidelines regarding who they deem appropriate for genetic testing (in fact I was denied testing by both a research study and my insurance…but that’s a rant for another day). However, there are lower cost testing options for people who still should/want to be tested but aren’t covered by insurance.
What are the options for people with BRCA mutations?
- Increased frequency of screening tests (breast MRIs, mammograms, transvaginal ultrasounds, CA-125 blood tests). However, early screening is much more effective for detecting early breast cancer than ovarian cancer.
- Removal of the ovaries/Fallopian tubes (salpingo-oophorectomy), usually before age 40 or at the completion of childbearing, which reduces the risk of ovarian cancer by about 80%.
- Medications (hormone therapy and/or chemoprevention)
- Prophylactic mastectomy (preventative removal of the breasts) which decreases the breast cancer risk by about 90%.
So there you have it, a general primer on BRCA. There’s an abundance of other information out there that I will no doubt we wading waist deep into before long, but I think this post covers the basics. If you’re reading this and have a specific question that I might be able to answer, or something you’d like to see covered more in a future post, let me know.