THE WOMEN’S HEALTH GROUP, P.C.

9195 Grant Street, Suite 410, Thornton, CO 80229

Phone: 303-280-2229 (BABY)

300 Exempla Circle, Suite 470,      Lafayette, CO 80026

Phone: 303-665-6016

www.whg-pc.com

  SCREENING FOR OVARIAN CANCER

Ovarian cancer is a nonspecific term for a variety of cancers that originate in the ovary. There are about 20 microscopically distinct types. They can be classified into three large groups, epithelial cancers, germ cell tumors, and specialized stromal cell cancers. There are three groups because the ovary contains collections of cells with three distinct origins and functions.

SCREENING FOR OVARIAN CANCER

There have been many attempts to screen for ovarian cancers. None have been shown to be worthwhile. Screening means looking for a cancer in a person who has no symptoms and who has no physical findings suggestive of a cancer.  The two methods used to try to screen for ovarian cancers are the Ca-125 blood test and ultrasound examinations. The reason that screening is not advised is because:

1.   The incidence of ovarian cancer is low. Of the approximately 40,000,000 women in this country who are of an age to be at risk there are only about 20,000 cancers diagnosed each year. This is only about 1 in 2,000. Since two thirds of the cancers are at an advanced stage at diagnosis that leaves only about 1 woman in 10,000 who would be both asymptomatic and have no physical findings. So, the incidence of finding an unsuspected ovarian cancer is very low on an annual basis.

2. There is no recognized progression from an early premalignant change to an early cancer to an advanced cancer. Screening will only be helpful if you can find a change before it turns into a cancer or find a very early cancer before it progresses to an advanced cancer. Unlike premalignant changes on the cervix that can be found with the Pap test, there is no such progression to cancer in the ovary that is known at this time.

3. The positive and negative predictive values of both the Ca-125 test and ultrasound techniques are too low. There are too many reasons for a positive test other than cancer. If the Ca-125 is elevated in a screened population where there is expected to be only 1 cancer in every 2,000-10,000 women, then it will be elevated for some other reason about 99 to 1 times. The positive predictive value is less than 1%. This means that for every 100 positive tests only one will be due to cancer. Likewise, a negative test is wrong half of the time in women with ovarian cancer and is therefore essentially meaningless. The Ca-125 is a good test to follow the results of treatment in a person already diagnosed with ovarian cancer but is of no value to use to go looking for cancers.

4. There is no easy way to evaluate an abnormal test. All you can do is say that your cancer test is positive but that it is probably wrong by a factor of 99 to 1, and maybe you should just forget about it. Or, you could repeat it in several months and pick the best two out of three results. Or, if you wish to pursue it, you will eventually have to remove the ovaries to prove that there is no cancer. Unlike the abnormal Pap test that can easily be evaluated as many times as you wish there is no easy way to evaluate an abnormal Ca-125 or ultrasound test.

5. There is no recognized professional organization that has evaluated this problem that recommends screening. It may be possible someday but not now.

Those with a documented familial ovarian cancer syndrome where the lifetime risk of developing ovarian cancer is about 50% are advised to have annual physical examinations and consider an annual pelvic sonogram. Those who have set up ovarian cancer screening programs for women with a family history of ovarian cancer have not reported any substantial benefit. Even if you decided to undergo regular Ca-125 and pelvic sonogram testing, how often should it be done? Every year seems not very adequate for ovarian cancer. How long should it be done? For the next 30 years?

FAMILIAL OVARIAN CANCER

It has been reported that from 1% to 5-10% of ovarian cancers are thought to be due to an inheritable syndrome. For those that are, the other female members of the family have a lifetime risk of about 50% of developing ovarian cancer. If there are several members in several generations with ovarian cancer then this may represent a familial syndrome. In general the lifetime risk of developing ovarian cancer is about 1.7%. If there is one first degree relative with ovarian cancer then the risk is about 3-5%. If there are two or more relatives with ovarian cancer then the risk is about 7%. Familial ovarian cancers tend to occur at an early age, before 50 years, and tend to be advanced serous epithelial cancers.

Those with a familial syndrome are advised to have their ovaries removed by age 35. There are no recommendations for women who have one or more relatives with ovarian cancer but no documented familial syndrome. They should also consider surgery since there is no good way to follow them and they may be at the beginning of a gene mutation. The gene responsible for familial ovarian cancer is thought to be the same as the one for some breast cancers. There is a commercially available test for this gene, but its usefulness is undetermined.

RISK FACTORS FOR OVARIAN CANCER

Epithelial ovarian cancers tend to be a cancer of affluent societies where expected life spans are long. An increased risk factor, other than age, is nulliparity or delayed childbearing. A decreased risk is seen with multiparity and with prolonged use of birth control pills. The mechanism for this protective effect is thought to be that the number of ovulations is reduced. Each ovulation requires the breakage of the ovarian follicle and the repair to the ovarian surface. A reparative process means increased cell divisions, or mitoses. Each mitotic event is a time of risk for a mutation to occur. There have been some unsubstantiated claims that the use of talcum powders contaminated with asbestos can cause ovarian cancers. Dietary factors are difficult to determine but if present are very weak in their association. One study has even associated yogurt with an increased risk. More recently there has been a purported increased risk with the use of fertility drugs. The cause of ovarian cancer is unknown.