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Ovarian Cancer

The Ovaries--How They Work

The ovaries are located in the pelvis, one on each side of the uterus. About the size and shape of almonds, they are made up of several different cell types. Some carry out the hormonal functions of the organ, while others provide physical support. The ovaries have two main functions:
ovulation (the release of an egg each month)
production of estrogen and progesterone, hormones that regulate the menstrual cycle and pregnancy and control the development of female physical traits, such as the breasts, pelvic structure, fat distribution, and body hair.
From birth, the ovaries contain the cells that eventually become ova (eggs). Each month, beginning with puberty and until menopause, hormones produced by the pituitary gland in the brain stimulate ovulation (release of an egg), which alternates each month between the two ovaries. (Not all women ovulate every month.)

The egg travels through the fallopian tube to the uterus. If it is fertilized, it may grow and develop in the womb. If not, hormone changes cause shedding of the uterine lining, and menstruation begins about two weeks later.


Benign Ovarian Cysts
Noncancerous ovarian cysts are a very common condition among women of reproductive age. But before diagnosing a condition as a benign ovarian cyst, doctors rule out cancer.

Normally, the follicle (or cyst) created by the ovaries each month bursts harmlessly when ovulation occurs. Sometimes, however, this normal physiologic process goes awry. The follicle, instead of bursting and releasing its egg, may continue to swell with fluid, or the corpus luteum (tissue that secretes hormones to prepare for pregnancy) may fail to dissolve even though the egg has not been fertilized. In either of these situations, the result is a "functional," or physiologic, cyst--a fluid-filled sac that may be as small as a grape or as large as a grapefruit.

Functional cysts are the most common ovarian cysts. In a premenopausal woman, such a cyst is always benign (noncancerous) and will frequently disappear spontaneously within a couple of months. Sometimes a functional cyst ruptures, spilling ovarian fluid into the abdominal cavity and causing pain. As the body absorbs the fluid, however, the pain subsides, and surgery is rarely necessary.

Ovarian cysts may be diagnosed by pelvic examination or by ultrasound imaging. A woman who has a functional cyst may have abdominal cramps, nausea, and menstrual irregularity. However, many women have no symptoms at all.

A gynecologist who diagnoses a cyst of less than 6 centimeters (2 1/4 inches) in diameter in a premenopausal woman who is ovulating will usually want to observe the patient for a couple of menstrual cycles to see if the cyst goes away by itself, says Lisa Rarick, M.D., director of FDA's division of reproductive and urologic drug products.

If the cyst doesn't disappear spontaneously, the doctor may recommend that the woman take birth control pills to suppress ovulation. Most birth control pills are combinations of two female sex hormones, estrogen and progestin. In some cases, progestin-only pills (also called "mini-pills") may be prescribed instead of combination pills. Both combination birth control pills and mini-pills work by preventing the release from the brain of other hormones that stimulate ovulation. Deprived of hormonal stimulation, a functional ovarian cyst will often shrink and eventually disappear.

An ovarian cyst that doesn't disappear after a couple of months may be a benign semisolid cyst. This kind of cyst is usually diagnosed by ultrasound imaging. The most common semisolid cyst is a dermoid cyst, so-called because it is made up of skin-like tissue; it can usually be removed by laparoscopic surgery. Occasionally, an ovary containing a dermoid cyst becomes twisted on itself, causing severe pain. Surgical removal of the affected ovary, or oophorectomy, may be necessary if this happens.

Any cyst that is 6 centimeters in diameter--about the size of a peach--or larger in a premenopausal woman should be investigated immediately as a possible malignancy, says Rarick, as should a cyst of any kind in a woman who has completed menopause.

While some doctors will recommend surgical examination of a large ovarian cyst, many gynecologists will examine the mass through a laparoscope, says Rarick. "It's possible to use a needle to puncture the cyst or aspirate its contents. The cyst can even be removed through the laparoscopic incision."

Polycystic ovarian disease, also known as Stein-Leventhal syndrome, is a benign condition characterized by multiple small cysts on the ovaries. This disease has a distinct set of symptoms that may appear as early as adolescence and may include menstrual irregularity, abnormal growth of body hair, lack of breast development, obesity, and infertility.

--Eleanor Mayfield

Taxol's Long History
The healing properties of Taxol were known to at least one community long before Western medicine recognized the drug's potential.

According to an article in the Sept. 4, 1991, Journal of the American Medical Association, around the turn of the century, a British official in the Indian subcontinent noted that parts of the European yew, Taxus baccata, were used in an Indian clarified butter preparation for treating cancer.

It wasn't until 1962, however, that the U.S. Forest Service delivered crude bark extracts of the Pacific yew, Taxus brevifola, to the National Cancer Institute. A series of NCI experiments showed the extract was effective against several kinds of cancer in mice.

In 1971, researchers at the Research Triangle Institute in Durham, N.C., isolated Taxol from the extract, but interest in the compound waned until the mid-1970s. In 1979, a researcher at Albert Einstein College of Medicine in New York described how Taxol works to defeat cancer by inhibiting cell division.

Today, Taxol--alone or in combination with other drugs--is being studied for a wide variety of adult and childhood cancers. In July 1992, FDA authorized use of the drug for ovarian cancer under a "treatment IND." Treatment INDs permit earlier and wider access to experimental drugs by patients with life-threatening conditions for which there is no satisfactory treatment.

Taxol was approved in December 1992 for advanced disease unresponsive to other therapies. The drug was approved in a record five months.

In April 1998, it was approved as a first-line therapy for advanced ovarian cancer.


Publication No. (FDA) 98-1206


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