Oophorectomy Health Article

Definition

Unilateral oophorectomy (also called an ovariectomy) is the surgical removal of an ovary. If one ovary is removed, a woman may continue to menstruate and have children. If both ovaries are removed, a procedure called a bilateral oophorectomy, menstruation stops and a woman loses the ability to have children.

Purpose

Oophorectomy is performed to:

• remove cancerous ovaries
• remove the source of estrogen that stimulates some cancers
• remove a large ovarian cyst
• excise an abscess
• treat endometriosis

In an oophorectomy, one or a portion of one ovary may be removed or both ovaries may be removed. When an oophorectomy is done to treat ovarian cancer or other spreading cancers, both ovaries are removed (called a bilateral oophorectomy). Removal of the ovaries and fallopian tubes is performed in about one-third of hysterectomies (surgical removal of the uterus), often to reduce the risk of ovarian cancer.

Oophorectomies are sometimes performed on premenopausal women who have estrogen-sensitive breast cancer in an effort to remove the main source of estrogen from their bodies. This procedure has become less common than it was in the 1990s. Today, chemotherapy drugs are available that alter the production of estrogen and tamoxifen blocks any of the effects any remaining estrogen may have on cancer cells.

Until the 1980s, women over age 40 having hysterectomies routinely had healthy ovaries and fallopian tubes removed at the same time. This operation is called a bilateral salpingo-oophorectomy. Many physicians reasoned that a woman over 40 was approaching menopause and soon her ovaries would stop secreting estrogen and releasing eggs. Removing the ovaries would eliminate the risk of ovarian cancer and only accelerate menopause by a few years.

In the 1990s, the thinking about routine oophorectomy began to change. The risk of ovarian cancer in women who have no family history of the disease is less than 1%. Meanwhile, removing the ovaries increases the risk of cardiovascular disease and accelerates osteoporosis unless a woman takes prescribed hormone replacements.

Under certain circumstances, oophorectomy may still be the treatment of choice to prevent breast and ovarian cancer in certain high-risk women. A study done at the University of Pennsylvania and released in 2000 showed that healthy women who carried the BRCA1 or BRCA2 genetic mutations that pre-disposed them to breast cancer had their risk of breast cancer drop from 80% to 19% when their ovaries were removed before age 40. Women between the ages of 40 and 50 showed less risk reduction, and there was no significant reduction of breast cancer risk in women over age 50. A 2002 study showed that five years after being identified as carrying BRCA1 or BRCA2 genetic mutations, 94% of women who had received a bilateral salpingo-oophorectomy were cancer-free, compared to 79% of women who had not received surgery.

The value of ovary removal in preventing both breast and ovarian cancer has been documented. However, there are disagreements within the medical community about when and at what age this treatment should be offered. Preventative oophorectomy, also called prophylactic oophorectomy, is not always covered by insurance. One study conducted in 2000 at the University of California at San Francisco found that only 20% of insurers paid for preventive bilateral oophorectomy (PBO). Another 25% had a policy against paying for the operation, and the remaining 55% said that they would decide about payment on an individual basis.

Demographics

Overall, ovarian cancer accounts for only 4% of all cancers in women. But the lifetime risk for developing ovarian cancer in women who have mutations in BRCA1 is significantly increased over the general population and may cause an ovarian cancer risk of 30% by age 60. For women at increased risk, oophorectomy may be considered after the age of 35 if childbearing is complete.

Other factors that increase a woman's risk of developing ovarian cancer include age (most ovarian cancers occur after menopause), the number of menstrual periods a woman has had (affected by age of onset, pregnancy, breastfeeding, and oral contraceptive use), history of breast cancer, diet, and family history. The incidence of ovarian cancer is highest among Native American (17.5 cases per 100,000 population), white (15.8 per 100,000), Vietnamese (13.8 per 100,000), white Hispanic (12.1 per 100,000), and Hawaiian (11.8 per 100,000) women; it is lowest among Korean (7.0 per 100,000) and Chinese (9.3 per 100,000) women. African American women have an ovarian cancer incidence of 10.2 per 100,000 population.