How many women get ovarian cancer?
Ovarian cancers are about 7 times less frequent than breast cancers with 1 in every 8 women expected to have a breast cancer diagnosis during their life time. Although fewer women get ovarian cancer, it is much deadlier. While breast cancer accounts for 16% of cancer deaths, ovarian cancer accounts for 6%. (
RETURN TO FAQ TABLE)Why is ovarian cancer so deadly?
Most ovarian cancers are detected late after they have spread beyond the ovary. These advanced tumors are associated with poor prognosis.
Small early detected ovarian cancers are the most treatable and are associated with high cure rates.
Failure to detect early stage disease is the single most important factor contributing to ovarian cancer mortality. Because manual pelvic examination has been the chief tool for ovarian cancer discovery, many small tumors in large women simply go detected. (
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What are the risk factors for ovarian cancer?
GENERAL RISK FACTORS
Ovarian cancer risk increases with age.
Women who have not had children, begin their reproductive cycles early and continue them longer have an increased risk of ovarian cancer.
Multiple childbirth, and oral contraception for more than two years confer some protection lowering the risk of ovarian cancer.
Thus, women who ovulate more have a greater ovarian cancer risk than those who have ovulated less.
HIGH RISK FACTORS
Familial ovarian cancer presents the highest risk to women who share this risk factor. Ovarian cancer families are generally thought to have two or more first degree relatives, like mother/sister/daughters, who have had ovarian cancer. Mothers, sisters and daughters and daughters share one half of their genes, so that this type of ovarian cancer which is inherited as an autosomal dominant, may have as high as a 50% chance of being diagnosed in these individuals.
INTERPRETING RISK FACTORS
Risk factors are really the chance that someone will get a disease. For diseases like ovarian cancer, risk factors should be interpreted in terms of:
As a general guide, the following table may be helpful.
|
Relative With Ovarian Cancer |
Example |
Risk |
|
None |
--- |
1.8 % |
|
1 First degree relative |
Mother |
7 % |
|
1 First & 1 second degree relative |
Mother & aunt |
> 7 % |
|
2 First degree relatives |
Mother & sister |
50 % |
(
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Are there known ovarian cancer genes?
The first gene linked to inherited ovarian cancers and breast cancers was discovered in 1994 and is known as BRCA1. A second gene, BRCA2, was discovered a year later.
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Can a person be tested for these genes?
Examination of DNA from white blood cells for abnormal or mutated forms of these genes is possible. However, there are over 400 mutations of the BRCA1 gene alone and inherited BRCA1 or BRCA2 mutations are different in different ovarian cancer families. Thus, a single simple test is not possible. (
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What are the chances of getting ovarian cancer if a person has abnormal changes in BRCA1 or BRCA2?
The estimated risk changes as more research information is published.
When BRCA1 was first discovered, the chance of a woman developing breast or ovarian cancer by age 70 if she carried a BRCA1 abnormality was 95%, with an 85% chance of breast cancer and a 60% chance of ovarian cancer.
However, these high estimates were gathered from families with numerous cases of breast and ovarian cancers.More recent estimates of risks of developing ovarian or breast cancer in individuals simply carrying mutations in BRCA1 or BRCA2 have been lower. Because variations in the ovarian cancer rate in these individuals show wide variations, counseling recommendations are difficult to make.
As a general guide, the following table may be helpful.
|
Gene Mutation |
Ovarian Cancer |
Breast Cancer |
|
BRCA1 |
20-40 % |
50-85 % |
|
BRCA2 |
15-20 % |
55-85 % |
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Should anyone get BRCA1 or BRCA2 gene testing?
BRCA1 or BRCA2 gene testing is not recommended for the general population since only 1 in 400 Americans are believed to carry mutations in these genes and these mutations are responsible for a small portion of all ovarian cancers.
Originally, genetic BRCA1/ BRCA2 testing was recommended only in a research setting for women with a family history of ovarian or breast cancer and those of an Ashkenazi Jewish background. This restriction has been lifted and testing coupled to counseling is available to these individuals. Appropriate counseling needs to insure that the person being tested has a thorough understanding of the implications of both positive and negative results, as well as of the possibilities of occasional false-positive or false-negative testing results.
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Because the risk is so high these women should seek advice about undergoing a prophylactic oophorectomy, by age 35 if they have completed their families.
This procedure can be done without hysterectomy by video laparoscopy, achieving low morbidity and minimal disruption to the lives of these women. The pelvis and abdomen should be carefully examined and the ovaries submitted for microscopic examination by a pathologist to make sure small ovarian carcinomas are not present. After surgery, these women should be given the option of hormone replacement therapy. (RETURN TO FAQ TABLE)
Can a woman get ovarian cancer after her ovaries have been removed?
Although the ovaries are no longer present from which ovarian cancer can arise, a small percentage (~1.8 %) of women with a family history of ovarian cancer who have had an oophorectomy, can develop a papillary carcinoma of the peritoneum which is identical in histological appearance to ovarian cancer. This can develop 1-27 years after oophorectomy. Women considering and receiving oophorectomy should be aware of this risk and should be evaluated annually. (RETURN TO FAQ TABLE)
What are the risks of estrogen/ progesterone hormone replacement therapy?
In 1997, 51 studies from 21 countries were reanalyzed and concluded that HRT increases the risks of breast cancer slightly in women who use it for 5 years or longer.
Surprisingly, the American Cance Society's Cancer Prevention Study found that in 422,373 women, use of HRT was associated with a 16% lower risk of dying from breast cancer.
As a general guide, the following table may be helpful.
|
Duration of Use |
Additional Breast Cancers |
Ovarian Cancer |
|
5 years |
+2/1000 |
None |
|
10 years |
+6/1000 |
None |
|
15 years |
+12/1000 |
None |
|
Stopped for 5years |
0/1000 |
None |
Taken together, these studies indicate that if there are adverse risks to HRT, they are likely to be small.
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