Joining FORCES is the FORCE newsletter with news, views and supportive information for individuals concerned about hereditary breast and ovarian cancer.
by Julie Huynh
"To identify a woman as a carrier only after she develops cancer is a failure of cancer prevention," says Dr. Mary-Claire King in her 2014 viewpoint article in The Journal of the American Medical Association.
As genetic testing becomes more affordable and available, the possibility of testing all women for BRCA mutations, often called population testing, has become more feasible. Often, women with BRCA mutations only become aware of their mutation after they have been diagnosed with cancer — either because their family cancer history was not known or recognized for a number of reasons, including small family size or inheriting the mutation from their father. While mutations in BRCA predispose carriers to high breast and ovarian cancer risks, knowing that you have a BRCA mutation provides access to many treatment and preventive options. However, while population testing would help identify women without a strong family history of breast cancer, costs also need to be considered.
To better understand the issues, FORCE convened a panel of experts at the 2015 Joining FORCEs closing session, including Anya Prince and Drs. Tuya Pal, Susan Vadaparampil, Timothy Rebbeck, and Olufunmilayo Olopade, to discuss the issue of BRCA population genetics and population testing.
Dr. Rebbeck discussed factors that must be considered when discussing population testing for BRCA. He outlined criteria for population testing for a disease and explained how BRCA population testing fits into these criteria:
1) Is it an important public health problem for other populations?
a. Yes, 1 in 400 people who are not of Ashkenazi Jewish decent will have a mutation.
2) Do mutations confer high risk?
a. Yes, for BRCA1 mutation carriers, the risk of developing breast cancer is approximately 46-59%, while the ovarian cancer risk is approximately 33-36%.
3) Do effective interventions exist?
a. Yes, proven preventive measures (e.g., breast screening, prophylactic breast and ovarian surgery) are available for people with BRCA mutations.
These criteria indicate that BRCA population testing is something worth considering. But, Dr. Rebbeck emphasized that related costs and benefits should also be examined. While the risk of developing breast cancer is high in mutation carriers, it is not 100%, meaning that not all women with BRCA mutations will develop breast or ovarian cancer. Unnecessary interventions may occur — if the risk is not 100%, someone will get tested, and someone will have an oophorectomy that was unnecessary because she would never develop ovarian cancer. From a public health perspective, the cost of testing, medical and psychosocial harm, and the potential to incur unnecessary interventions need to be weighed against the breast cancers prevented, especially in non-Ashkenazi Jewish populations.
Anya Prince talked about population testing from a policy perspective, focusing on how it could be implemented. She is working on the GeneScreen research project to determinewhether a public health program screening asymptomatic adults for rare and medically actionable mutations is feasible, ethical, and socially sound. She raised a number of questions that must be considered before population testing can be implemented, including:
The closing session ended with Drs. Tuya Pal and Susan Vadaparampil presenting the pros and cons of BRCA population testing. They apply established criteria for population screening to the proposal to test all women at age 30, regardless of family history.
BRCA population testing offers many advantages. Breast cancer is an important public health problem, and the high breast cancer risk for BRCA mutation carriers is known. However, most studies have been done in people with known family histories of breast cancer; whether the level of risk in the general population will be the same is unknown. Will the risk for breast cancer be as high for people with a BRCA mutation but no family history of breast cancer as it is for those with a family history?
In terms of BRCA testing itself, population testing would potentially increase access to testing, and thus screening and risk-reducing measures. However, it is not known if all women will accept genetic testing. The role of pre-test genetic counseling and informed consent before testing must be explored on a population basis.
Regarding the pros and cons of population testing, when talking about risk management for BRCA mutation carriers, a pro is that guidelines for managing breast and ovarian cancer risk are already established. However, while they effectively prevent breast and ovarian cancer, it is unclear if these risk management options will be acceptable to all populations.
Finally, Drs. Pal and Vadaparampil considered the cost of testing to the health care system as a whole. Research shows that population based BRCA testing is cost effective in the Ashkenazi Jewish population where BRCA mutations are more prevalent. The cost in a more diverse population is not yet established. They concluded that population testing holds the potential for identifying more BRCA mutation carriers, and would remove known barriers to testing in the United States. However, more research needs to be done on the risk of cancer in people with BRCA mutations and no family history. In addition, the role of genetic counseling and assuring all patients have proper informed consent before testing must be addressed.
Dr. Olufunmilayo Olopade closed the forum with a call to action. She said that people can argue about testing penetrance. We know that everyone with a mutation is not going to get cancer. Individuals with mutations have different ways to manage their risk: some want only screening, while others want surgery. People are unique, but we need to give them the chance to make their own decisions about what they want. We should not be paternalistic and say that people will not know how to handle it.
The time is now, Dr. Olopade said. We have more work to do — the work is not done. Olopade finished by saying: I think what we need to do is think about prevention and early detection, and we're not going to get it by doing business as usual.
Julie Huynh is a Research Associate at FORCE.