BRCA Genes and Cancer Outcomes
By Rachel Walden — December 21, 2011
You may have seen recent news coverage along the lines of “BRCA variants not tied to worse cancer outcomes.” This story refers to a recently published study about changes in the BRCA1 and BRCA2 genes that affect breast and ovarian cancer. Women with mutated versions of the genes have greater risks of breast and ovarian cancer than women with typical versions of the genes.
In the new study in the Journal of Clinical Oncology, researchers tried to figure out whether women with BRCA1 or BRCA2 mutations who do develop cancer have worse outcomes than women without the mutations. They compared records for women with breast cancer and one of the mutations with those of women with breast cancer who did not have these gene changes.
Overall, they found that women with BRCA1 mutations had similar rates of metastatic (“distant”) cancer recurrence and death as women without it. Women with BRCA2 mutations had higher risks of recurrence and death, although the risk was similar when the women got adjuvant therapy (additional treatment to help prevent recurrences). Other factors like age and stage of the cancer also made a difference.
However, this study should be interpreted with caution. Bigger studies are probably still needed to properly understand any effects of these genes on women’s cancer therapy outcomes. The similarity of outcomes between women with and without the mutations may have to do, in part, with what we have learned about therapies for women with those mutated genes – which therapies don’t work as well for them, and which therapies might be added on for better outcomes. The researchers for the current study do say that women with mutated BRCA1/2 genes were more likely to have received adjuvant therapy, and the authors were unable to look at women’s results by how much chemotherapy they received.
While women who have BRCA1/2 mutations may be advised to have earlier or more frequent cancer screenings than other women, it’s not yet completely clear who should get tested for these mutations or if women should be tested once they’re diagnosed with breast or ovarian cancer.
As we learn more about how our genes affect our cancer risks and therapy outcomes, I expect we’ll see more and more news on these topics, and it may take some time to figure out how to assess risk, guide cancer therapies, and how our outcomes change based on this knowledge. Here are a few helpful resources for this growing area of study:
- Genetics Home Reference – Cancers – information from the National Library of Medicine on genes related to a number of cancers
- General Cancer Genetics Information – information from the National Cancer Institute on genetic (hereditary) risks for cancer, gene testing, a dictionary of genetics terms, and other resources
- My Cancer Genome – information intended to help inform physicians about tumor (not hereditary) genes and their effect on cancer therapy. Disclosure: I work with the team that produces this site.