Tuesday, June 23, 2015

Breast Cancer Awareness Month and BRCA mutations

In honor of breast cancer awareness month, I thought I'd write about 2 highly pertinent topics: BRCA testing and automated whole breast ultrasound.
You may be familiar with BRCA gene mutations. Angelina Jolie famously had a preventive double mastectomy in 2013 after she was found to be a carrier for one of these mutations. There are 2 known genes, BRCA-1 and BRCA-2. Mutations in these genes significantly increase a woman's risk of both breast and ovarian cancer.
BRCA has been back in the news lately thanks to a study from Mary-Claire King, the researcher who first identified BRCA-1.
The study found that even women who have no family history of breast cancer can carry a BRCA gene mutation and that it increases their risk by the same amount as women who do have a family history.
Here's the problem: the study was done in a particular ethnic group known as Ashkenazi Jews who have a much higher rate of BRCA gene mutations than the general population.
Dr. King has called for universal screening for ALL women regardless of ethnicity  based on these findings even though the prevalence in the general population is much lower. Most non-Ashkenazi Jewish women with breast cancer do not have a BRCA mutation. Screening everyone may lead to an increased number of false positives as well as increased false sense of security. I worry that women will get tested, get a negative result and then neglect routine breast cancer screening as a result. After all, 1 in 8 women will get breast cancer in their lifetime and most of these do not carry a BRCA mutation. Screening may also lead to women having unnecessary radical surgeries like mastectomies and oophorectomies. On the plus side, some women may be more proactive about their screening and may get additional tests like breast MRI or may take a medication to reduce their risk, however we already have a well established risk predictor model called the Gail Breast Cancer Risk Model as well as criteria for who should get BRCA testing. Instead of universally testing all women for a mutation that they are unlikely to have, I would like to see primary care doctors using these risk models and talking to women about their personal risk and what the screening options are.
Which leads me to a new screening tool for breast cancer. Some of you may have noticed that you now get a notification from you breast radiologist that you have "dense breasts". Your breasts are considered dense if you have a lot of fibrous or glandular tissue but not much fat.Dense tissue appears white on a mammogram. Lumps, both benign and cancerous also appear white so dense breasts make it more difficult for doctors to spot cancer on mammograms.
A JAMA study published in 2008 shows that when adding ultrasound to mammographic screening, researchers found an additional 1.1 to 7.2 cancers per 1,000 in women with dense breasts.
So if you have a history of dense breasts, ask your doctor if additional breast ultrasound would be right for you.

No comments:

Post a Comment