Links may be found on the BRCA 1/2 Gene Testing (General) page of our LATESTBreastCancer.com website.
The risk of cancer in the other breast
It is understood that women with BRCA mutations have a higher risk of developing breast cancer, but how do they do once diagnosed with breast cancer?
A study from the Netherlands found that women with breast cancer who carry a BRCA 1 or BRCA 2 gene mutation have a higher risk of developing cancer in the opposite breast than non-carriers. Medical News Today and MSN/HealthDay covered the Symposium presentation.
The study followed 5,061 women with cancer in one breast for about 8 years. 211 women carried a BRCA 1 or BRCA 2 gene mutation. For women with a BRCA mutation, the 10-year risk of developing cancer in the opposite breast was 17.6 percent, compared to a 6 percent risk for non-carriers.
Age at diagnosis affected risk. For BRCA carriers first diagnosed before the age of 40, the 10-year risk was 26 percent. For those diagnosed between 40 and 50, the risk was 11.6 percent.
Triple-negative status also mattered. Triple-negative BRCA carriers had a 10-year risk of 18.9 percent, compared to 11.2 percent for BRCA carriers who were not triple-negative.
In her blog from the Symposium, Dr. Susan Love noted,
Of note, most of the women in this study had not had their ovaries out, which decreases the risk of second cancers significantly (70%). The study also found that both chemotherapy and hormonal therapy for the first cancer seemed to reduce the chance of getting a second cancer in the other breast. In this era of bilateral mastectomies, it was a good reminder that the risk to the other breast is not the same in everyone.The risk of metastasis and death
Not all BRCA news this month came from the conference. A December Reuters piece discussed a recent Journal of Clinical Oncology (Dec. 5) study which compared survival differences among BRCA 1 mutation carriers, BRCA 2 carriers and non-carriers with breast cancer. Over 3,000 women were included. 90 had BRCA 1 mutations and 70 had BRCA 2 mutations.
The study found no difference in risk of metastasis and death between non-carriers and those with BRCA 1 mutations.
On the other hand, women with BRCA 2 mutations had a significantly higher risk of metastasis and breast cancer death. This may be explained by the fact that BRCA 2 carriers had worse tumors at diagnosis. When compared to women with similar age, tumor stage, nodal status and hormone receptor status, there was no difference in risk.
For BRCA 2 carriers, risk of death could be reduced with standard breast cancer treatment. For BRCA 2 carriers who did not receive chemotherapy, the risk of death increased over 300 percent. According to the lead study author, quoted in Reuters Health, "A lot of these women with genetic predisposition may develop tumors that have poor characteristics. . . But if they get standard treatment available they seem to do OK."
The risk of cancer at an earlier age
One study presented at the Symposium asked if the source of a BRCA 1/2 mutation, from the carrier's father or mother, affected breast cancer risk. US News and World Report/HealthDay covered the study on December 8.
Interestingly, for women with BRCA 1 mutations, those who inherited it from their mother were on average 45 at diagnosis. Those with BRCA 1 mutations from their fathers were on average 38.
For women with maternal BRCA 2 mutations, the average age at diagnosis was 50, compared to 41 for those with paternal BRCA 2 mutations.
The lead researcher noted that if confirmed in larger studies, "doctors might think about watching and waiting in young women" with maternal BRCA mutations and "being more aggresive" in young women with paternal mutations.
The risk of cancer for non-carriers from a family of BRCA carriers
What about women who do not carry a BRCA mutation, but come from a family of carriers? Are they at increased risk?
A Journal of Clinical Oncology study from Stanford studied 3,047 families with this question in mind. 160 families had BRCA 1 mutations. 132 had BRCA 2 mutations. Reuters discussed the results on October 31.
The study found "no evidence of increased breast cancer risk" for non-carriers from BRCA families compared to women with first-degree relatives from non-BRCA families. The authors concluded, "These results support the practice of advising noncarriers that they do not have any increase in breast cancer risk attributable to the family-specific BRCA1 or BRCA2 mutation."
These are only the latest research developments for BRCA mutation carriers. At LATESTBreastCancer.com, we follow breast cancer news and research daily. We add links to our website, sorted by treatment type. You may explore any time by clicking the Treatments tab.
Tomorrow's blog will highlight the latest news from the San Antonio Breast Cancer Symposium for women with metastatic breast cancer. Please stay tuned.