Prophylactic oophorectomy (o-of-uh-REK-tuh-me) significantly reduces your odds of developing breast cancer and ovarian cancer if you're at high risk. Weigh the pros and cons of this cancer-prevention option.

By Mayo Clinic Staff

Women with BRCA1 or BRCA2 gene mutations have a significantly increased risk of developing breast cancer and ovarian cancer. Several options are available for reducing the risk of cancer in these women.

One option is preventive (prophylactic) bilateral oophorectomy — the surgical removal of the ovaries. Although removing your ovaries is usually performed to reduce the risk of ovarian cancer, oophorectomy can also reduce the risk of breast cancer.

In an oophorectomy, a surgeon removes both your ovaries — the almond-shaped organs on each side of your uterus. Your ovaries contain eggs and secrete the hormones that control your reproductive cycle.

Removing your ovaries greatly reduces the amount of the hormones estrogen and progesterone circulating in your body. This surgery can halt or slow breast cancers that need these hormones to grow.

Women with BRCA gene mutations usually also have their fallopian tubes removed at the same time (salpingo-oophorectomy) since they have an increased risk of fallopian tube cancer as well.

Prophylactic oophorectomy is usually reserved for women with a significantly increased risk of breast cancer and ovarian cancer due to an inherited mutation in the BRCA1 or BRCA2 gene — two genes linked to breast cancer, ovarian cancer and other cancers. Women who have inherited mutations and have completed childbearing are the best candidates for this surgery.

Prophylactic oophorectomy may also be recommended if you have a strong family history of breast cancer and ovarian cancer but no known genetic alteration. It might also be recommended if you have a strong likelihood of carrying the gene mutation based on your family history but choose not to proceed with genetic testing.

If you have a BRCA mutation, a prophylactic oophorectomy can reduce your:

  • Breast cancer risk by up to 50 percent in premenopausal women. As an example, if a woman with a high risk of breast cancer had a 60 percent chance of being diagnosed with breast cancer at some point in her lifetime, bilateral oophorectomy could reduce her risk to 30 percent.

    Put another way, for every 100 women just like her, 60 could be expected to be diagnosed with breast cancer without oophorectomy. And 30 would be expected to be diagnosed with breast cancer after oophorectomy.

  • Ovarian cancer risk by 80 to 90 percent. As an example, if a woman with a high risk of ovarian cancer had a 30 percent chance of being diagnosed with ovarian cancer at some point in her lifetime, oophorectomy could reduce her risk to 6 percent, assuming an 80 percent risk reduction.

    Put another way, for every 100 women just like her, 30 could be expected to be diagnosed with ovarian cancer without oophorectomy. And six would be expected to be diagnosed with ovarian cancer after oophorectomy.

In studies, the risk of breast cancer and ovarian cancer varies. And your individual risk of breast cancer and ovarian cancer varies depending on many factors, including your family history, your lifestyle choices and other strategies you're using to reduce your risk of cancer. For some women, oophorectomy may offer great reduction in risk. For other women, the risks of surgery and the potential side effects may not be worth the reduction in cancer risk.

Oophorectomy is a generally safe procedure that carries a small risk of complications, including infection, intestinal blockage and injury to internal organs. The risk of complications depends on how the procedure is performed.

But more concerning is the impact of losing the hormones supplied by your ovaries. In women who have yet to undergo menopause, oophorectomy causes early menopause. Early menopause carries many risks, including:

  • Bone thinning (osteoporosis). Removing your ovaries reduces the amount of bone-building estrogen your body produces. This may increase your risk of a broken bone.
  • Discomforts of menopause. Hot flashes, vaginal dryness, sexual problems, sleep disturbance and sometimes cognitive changes are problems for some women during menopause. Removing your ovaries doesn't mean you'll immediately have these problems, but it does mean that any menopausal symptoms you develop will occur earlier and are more likely to reduce your quality of life than if they occurred during natural menopause.
  • Increased risk of heart disease. Your risk of heart disease may increase if you have your ovaries removed.
  • Lingering risk of cancer. Prophylactic oophorectomy doesn't completely eliminate your risk of breast cancer or ovarian cancer. A type of cancer that looks and acts identical to ovarian cancer can develop after the ovaries and fallopian tubes are removed. The risk of this type of cancer, called primary peritoneal cancer, is low — much lower than the lifetime risk of ovarian cancer if the ovaries remain intact.

Prophylactic oophorectomy might relieve much of your anxiety about developing either disease, but this type of surgery can also take an emotional toll on you. Even if you didn't plan on having children, you might mourn the loss of your fertility. Or you may, like some, have a strong sense of femininity tied to your fertility and reproductive cycle.

Use of low-dose hormone therapy after oophorectomy is controversial. While studies have shown that use of hormone therapy after menopause may increase a woman's risk of breast cancer, other studies suggest early menopause can cause its own serious risks.

Women who undergo prophylactic oophorectomy and don't use hormone therapy up to age 45 have a higher rate of premature death, cancer, heart disease and neurological diseases. For this reason, doctors typically recommend that younger women who have surgically induced menopause should consider taking low-dose hormone therapy for a short time and stop by ages 50 to 52.

It isn't entirely clear what effect hormone therapy might have on your cancer risk. Several studies have found that short-term hormone therapy doesn't increase the risk of breast cancer in women with BRCA mutations who have undergone prophylactic oophorectomy. Ask your doctor about your particular situation. If you decide to take low-dose estrogen, plan to discontinue this treatment after ages 50 to 52.

You may opt to have your uterus removed during your oophorectomy surgery so that you can take a type of hormone therapy (estrogen-only hormone therapy) that may be safer for women with a high risk of breast cancer. Discuss the benefits and risks of hysterectomy with your surgeon.

Researchers are studying other ways to reduce the risk of ovarian cancer in women who have a high risk of the disease. But these other ways of preventing ovarian cancer haven't been proved to reduce risk as much as oophorectomy has. For this reason, for most women with BRCA mutations, doctors recommend oophorectomy.

But oophorectomy isn't right for every woman with a high risk of breast cancer or ovarian cancer. So talk about the alternatives with your doctor to better understand how they may affect your risk. Options include:

  • Increased screening for ovarian cancer. You may choose to have ovarian cancer screening twice each year to look for early signs of cancer. Screening usually includes a blood test for cancer antigen CA 125 and an ultrasound exam of your ovaries.

    In theory, increased screening should be able to help doctors catch ovarian cancer at its earliest stages, but whether that's possible with current screening methods isn't clear. Screening tests are noninvasive, but there's no evidence that they save lives.

  • Birth control pills. Studies suggest that taking birth control pills reduces the risk of ovarian cancer in average-risk women. There is good evidence that birth control pills can reduce the risk of ovarian cancer and can also be beneficial in reducing risk in high-risk women, such as those with BRCA mutations.

    There is some concern that birth control pills may increase the risk of breast cancer in this high-risk group of women. However, the benefits of reducing ovarian cancer risk seem to outweigh the small risk of breast cancer.

Yes. Surgery to remove your breasts (bilateral mastectomy) may reduce your risk of breast cancer by 90 percent. As an example, if your risk of developing breast cancer at some point in your lifetime is 50 percent, a preventive mastectomy may lower your risk to 5 percent.

Put another way, for every 100 women who underwent preventive mastectomy, 5 could be diagnosed with breast cancer at some point in their lives.

Reasons a woman might choose oophorectomy over mastectomy include:

  • Oophorectomy reduces your risk of two cancers. Oophorectomy reduces your risk of both breast cancer and ovarian cancer, while mastectomy reduces only the risk of breast cancer.
  • There aren't many options for preventing ovarian cancer. Ovarian cancer is sometimes seen as a greater threat than breast cancer because it isn't easily detected, and it may be detected at a later stage when diagnosed. There are tests, such as mammograms and breast MRIs, to detect breast cancer at an early stage in very high-risk women.
  • Removing your ovaries doesn't affect your appearance. Some women are concerned about how they'll look if they have their breasts removed. Oophorectomy won't affect your appearance.

These benefits have to be balanced against the risks of oophorectomy and the early menopause that occurs as a result.

The decision to have prophylactic oophorectomy is a challenging and difficult one with no clearly right or wrong answer. It comes down to a personal choice you alone can make, but advice from a genetic counselor, a breast health specialist or a gynecologic oncologist can help you make a more informed decision.

Questions to ask your doctor or other health care provider include:

  • What is my risk of breast cancer?
  • What is my risk of ovarian cancer?
  • What are my options to lower my risk of breast cancer?
  • What are my options to lower my risk of ovarian cancer?
  • What are the benefits and risks of each option?
  • What are some good sources of information about reducing my cancer risk?
  • How much time can I take to research my options and make a decision?
  • If I decide that prophylactic oophorectomy isn't right for me right now, can I change my mind later?
  • What advice would you give your friend or family member if she were in my situation?

Determining whether prophylactic oophorectomy is right for you — and when it might be right for you — depends on your individual risk of cancer and how aggressive you want to be in your cancer-prevention efforts.

Apr. 14, 2014