Removing Ovaries and Fallopian Tubes Reduces Risk of Certain Cancers in Women Who Have Abnormal BRCA1 or BRCA2 Genes
Reviewed study: "Removing Ovaries and Fallopian Tubes Reduces Risk of Certain Cancers in Women Who Have Abnormal BRCA1 or BRCA2 Genes" by Steven Narod and others, Journal of the American Medical Association, July 12, 2006
Is this for me? If you know you have an abnormal BRCA1 or BRCA2 gene and are considering removing your ovaries and fallopian tubes to reduce your risk of cancer, you might want to read this article.
What question is the study trying to answer? The researchers wanted to estimate the absolute risk of developing cancer in the ovaries, fallopian tubes, and lining of the abdomen (known as gynecologic cancers) for women who have an abnormal BRCA1 or BRCA2 gene. (BRCA stands for BReast CAncer.) They also wanted to know the extent to which women could reduce this risk by having surgery to remove the ovaries and fallopian tubes.
The average woman (without an inherited breast cancer gene abnormality) in the United States has about a 12% risk of developing breast cancer over a 90-year life span. In contrast, women who have an abnormal BRCA1 or BRCA2 gene have up to an 85% risk of developing breast cancer by age 70.
Women with an abnormal BRCA1 or BRCA2 gene also have an increased risk (ranging from about 15% to 60%) of developing ovarian cancer. Abnormal BRCA1 and BRCA2 genes also increase a woman's risk for cancer of the fallopian tubes and peritoneum (the lining of the abdomen).
Women with an abnormal BRCA1 or BRCA2 gene may consider having their ovaries and fallopian tubes removed (this is called protective surgery) to reduce their risk of ovarian, fallopian tube, and peritoneal cancer. Small studies estimate that the protective surgery reduces relative risk from between 80% to 95%. According to the researchers, the study reported here is the largest study yet to estimate risk reduction in this population.
Study design: A total of 1,828 women from the United States, Canada, Europe, and Israel with a known abnormal BRCA1 or BRCA2 gene were divided into 3 groups:
- Group I: 555 women (30%) had protective surgery to remove their ovaries and fallopian tubes before the study began.
- Group II: 490 women (27%) had the protective surgery after the study began.
- Group III: 783 women (43%) did not have protective surgery.
The women were enrolled in the study from 1992 to 2003.
The researchers recorded how many women in each group were diagnosed with ovarian, fallopian tube, or peritoneal cancer.
The women were followed for about 3.5 years and had the following characteristics:
- their average age was about 47
- 1,380 women (75.5%) had an abnormal BRCA1 gene
- 440 women (24.1%) had an abnormal BRCA2 gene
- 8 women (0.4%) had both abnormal BRCA1 and BRCA2 genes
The study was funded by the Canadian Breast Cancer Research Alliance and the National Institutes of Health.
Study results: After 3.5 years of follow-up, 32 cases of ovarian, fallopian tube, or peritoneal cancers were diagnosed in women who did not have protective surgery, compared to just 11 cases in women who did have protective surgery.
Group III: No surgery before the study (786 women)
Of the 32 women in this group who developed gynecologic cancers:
- their age at diagnosis ranged from 34 to 72 years old
- 29 women had an abnormal BRCA1 gene
- 3 women had an abnormal BRCA2 gene
- 24 women had a personal history of breast cancer
Group II: Surgery done after the study started (490 women)
Of the 11 women who were diagnosed with cancer when the protective surgery was done (after the study began):
- their age at diagnosis (when they had surgery) ranged from 38 to 68 years old, and 8 of the 11 women were younger than 50
- 9 women had an abnormal BRCA1 gene
- 2 women had an abnormal BRCA2 gene
- 8 women had a personal history of breast cancer
Group I: Surgery done before the study started (555 women)
Of the 7 women diagnosed with cancer who had had protective surgery before the study began:
- their age at diagnosis ranged from 36 to 55 years old, and on average they had had their surgery about 5 years before
- 6 women had an abnormal BRCA1 gene
- 1 woman had an abnormal BRCA2 gene
- 3 women had a personal history of breast cancer
The researchers estimated that the risk of ovarian, fallopian tube, and peritoneal cancers was reduced by 80% in women with an abnormal BRCA1 or BRCA2 gene who had protective surgery to remove the ovaries and fallopian tubes.
What breastcancer.org says about this article…
Removing Ovaries and Fallopian Tubes Reduces Risk of Certain Cancers in Women Who Have Abnormal BRCA1 or BRCA2 Genes
If you are at high risk of developing ovarian and other cancers because of an abnormal breast cancer gene, you may be seriously considering extra protective measures to reduce your risk. Making lifestyle changes might help lower your risk somewhat. Medications like tamoxifen can also help. But when you are facing a very high risk, it's necessary to also consider more aggressive measures, such as surgery. Protective surgery to remove your ovaries and fallopian tubes is a serious option that provides powerful protection against cancers of these structures, but it can also have a significant impact on quality of life. If you are pre-menopausal, this surgery can make you go into permanent menopause.
If you have an abnormal BRCA1 or BRCA2 gene and want to be as aggressive as possible about your care, talk to your doctor about the role of removing your ovaries and fallopian tubes to lower your risk of developing ovarian cancer.
The timing of protective surgery is important. The whole idea is to get the organs out before cancer has a chance to form in them. The younger you are when you have protective surgery, the greater the chance that the surgery will remove these structures before any cancer starts. The longer you wait to have the surgery, the greater the risk of cancer starting while the organs are still in you.
In their discussion of this study, the researchers recommend that women with an abnormal BRCA1 or BRCA2 gene consider protective removal of the ovaries and fallopian tubes by age 35 in order to get maximum protection. In this study, many of the ovarian cancers diagnosed were in women no older than age 38. By the time women with an abnormal BRCA1 gene in this study were 50 years old, 6% of them had ovarian cancer at the time of protective surgery. While early timing is important, though, this surgery is not an emergency. You have time to understand your own risk and consider your options.
You might also be aware that removal of the ovaries (without breast removal) in a pre-menopausal woman with a breast cancer gene abnormality can reduce her risk of breast cancer by 50%, or half (an 80% risk drops down to 40%). This important point was not a focus in this study.
With your doctor, balance the potential benefits of protective surgery against the side effects. For example, family planning issues may be a concern, whether you've already had children or want to have children in the future. Talk to your doctor or genetic counselor about the risks and benefits of waiting to have surgery until after you've had children. The decision to have protective surgery at any age requires much thought, and must be made in consultation with your doctor, psychological counselor, and other health care professionals as needed.