BRCA type sways benefit of anti-cancer surgery
By Anthony J. Brown, MD
NEW YORK (Reuters Health) - Women with BRCA1 and BRCA2 gene mutations can lower their risk of developing breast and gynecologic cancers by having their ovaries removed. However, the benefit depends on which mutation they have, researchers have found.
Ovary removal significantly reduces the odds of gynecologic cancer in BRCA1 carriers and the risk of breast cancer in BRCA2 carriers, Dr. Noah D. Kauff, from Memorial Sloan-Kettering Cancer Center in New York, and his associates report.
"All previous studies have either combined BRCA1 and BRCA2 mutation carriers together or evaluated BRCA1 mutation carriers alone," Kauff explained to Reuters Health. "As many as 39 percent of all BRCA mutation carriers have a mutation in BRCA2 and these women may have very different responses to risk-reducing interventions than women with BRCA1 mutations."
The most important finding of the study, he said, "is that carriers of BRCA2 mutations appear to receive substantially greater protection against breast cancer from (ovary removal) than carriers of BRCA1 mutations. As this issue has never been evaluated before, this is new information and surprising."
The study, reported in the Journal of Clinical Oncology, involved more than 1000 women with a BRCA1 or BRCA2 mutation, who made the decision to undergo ovary surgery or to just have regular cancer check-ups.
Compared to the women who did not have surgery, those who underwent removal of their ovaries were 85 percent less likely to develop BRCA1-associated gynecologic cancers over a 3-year period, and 72 percent less likely to develop BRCA2-associated breast cancer.
The surgery also reduced risks of BRCA2-associated gynecologic cancer and BRCA1-associated breast cancer, but these results were not significant from a statistical standpoint.
"These findings should help women with BRCA mutations and their doctors make more informed choices about strategies to reduce their risk of breast and gynecologic cancers," Kauff said.
SOURCE: Journal of Clinical Oncology, online February 11, 2008.
What breastcancer.org says about this article…
BRCA type sways benefit of anti-cancer surgery
Women with an abnormal BRCA1 or BRCA2 gene have a much higher than average risk of both breast and ovarian cancers. One aggressive way to lower the risk of both cancers is to remove the ovaries. This is called prophylactic (protective) oophorectomy (oo-for-EK-tuh-mee).
The study reviewed here shows that the amount of breast and ovarian cancer risk reduction after prophylactic ovary removal varies depending on the type of gene abnormality.
In women with an abnormal BRCA1 gene, removing the ovaries was more beneficial for lowering ovarian cancer risk (risk was reduced by 85%) than for lowering breast cancer risk (39% risk reduction).
In women with an abnormal BRCA2 gene, removing the ovaries was beneficial for lowering breast cancer risk (72% risk reduction), but the researchers couldn't tell how much it reduced ovarian cancer risk.
The large study looked at more than 1,000 women with either an abnormal BRCA1 or BRCA2 gene. The women decided to have either prophylactic ovary removal or to be monitored by their doctors.
Ovary removal and breast cancer risk:
Women who DON'T have an inherited breast cancer gene abnormality have about a 12% risk of developing breast cancer over their lifetimes. Women who DO have an abnormal BRCA1 or BRCA2 gene have up to an 85% risk of developing breast cancer by age 70. This study found that lowering breast cancer risk by removing the ovaries before menopause was less beneficial for women with an abnormal BRCA1 gene compared to women with an abnormal BRCA2 gene.
Removing the ovaries gets rid of the main source of hormones that can make hormone-receptor-positive breast cancers grow. Removing the ovaries may not be as beneficial for women with an abnormal BRCA1 gene because these breast cancers are much more likely to be hormone-receptor-negative. Breast cancers in women with an abnormal BRCA2 gene are more likely to be hormone-receptor-positive. This might explain why the study found more breast cancer risk reduction from ovary removal in women with an abnormal BRCA2 gene.
Ovary removal and ovarian cancer risk:
Women who DON'T have an abnormal BRCA1 or BRCA2 gene have less than a 2% risk of developing ovarian or other gynecologic cancer during their lifetimes. Women who have an abnormal BRCA1 gene have a lifetime ovarian cancer risk of about 55% (if they don't take steps to lower their risk). Women who have an abnormal BRCA2 gene have a lifetime ovarian cancer risk of about 25%. This study found that the reduction in ovarian and related cancers risk from ovary removal before menopause wasn't as large or as certain in women with an abnormal BRCA2 gene, compared to women with an abnormal BRCA1 gene. The researchers weren't sure why this was the case.
If you learn that you have an abnormal BRCA1 or BRCA2 gene, talk your doctor about ALL of the options that can lower your risk for both breast and ovarian cancer. Removing the ovaries is only one option. Some women may decide to have prophylactic removal of both breasts. There are also medicine options, depending on your menopausal status. Medicines can be used to shutdown the ovaries and hormonal therapies can block estrogen effects or lower estrogen production. Together, you and your doctor can decide on the best risk reduction plan for your unique situation.
