Some Facts on Ovarian Cancer
Cancer of the ovaries strikes approximately 19,000 women and causes 12,000 deaths in the
United States each year. It accounts for 10 percent of all cancers among women. It is
estimated that one of every 70 newborn girls will develop ovarian cancer in her lifetime.
Women between the ages of 65 and 84 are most likely to develop ovarian cancer, although it does occur among younger women and even among children. There are often no obvious signs or symptoms until the cancer has spread.
The Function of the Ovaries
The ovaries are a pair of female reproductive glands, each about the size and shape of a
large almond shell, that produce and release the ova or egg each month. The egg then moves
into one of the two fallopian tubes. If the egg is fertilized by sperm, it passes into the
uterus where the fetus develops. If it is not fertilized, menstruation occurs.
The ovaries also produce the female hormones estrogen and progesterone. These hormones are necessary for a woman to become pregnant. The amount of these hormones decreases gradually as a woman approaches the age of menopause, when menstruation stops.
Most ovarian cancers are epithelial, originating in the line tissues of the ovary. Rarer forms of ovarian cancer occur in the stroma, the connective tissue that supports the ovary, and in the germ cells, those that form the egg.
What is Cancer?
Cancer is really a number of diseases caused by the abnormal growth of cells. Normally,
the cells that make up the body divide and reproduce in an orderly manner, so that we can
grow, replace worn-out tissue, and repair any injuries. Sometimes, however, cells get out
of control. They divide too rapidly and form masses known as tumors.
Some tumors may interfere with body functions and require surgical removal, but they do not spread to other parts of the body. These are known as benign tumors. Malignant -- or cancerous -- tumors not only invade or destroy normal tissue, but, by a process known as metastasis, cells break away from the original tumor and migrate to other parts of the body. There they may form additional malignant tumors.
Ovarian cancer tends to spread quickly throughout the abdominal area. It may also involve distant lymph glands, the liver, and the lungs. Approximately 10 percent of all ovarian cancer originates elsewhere and then spreads to the ovaries, usually from the breast or bowel.
Ovarian Cancer Risk Factors
The cause of ovarian cancer remains unknown, but several factors are associated with an
increased risk of developing it. The primary factor is age; women over 40 are considered
at high risk and women 65 to 84 are in the highest risk category. Other risk factors
include a family history of ovarian cancer, a personal history of breast cancer, and
obesity. Ovarian cancer and cancers of the bowel, breast, and endometrium (the membrane
that forms the inner wall of the uterus seem to be associated with dietary factors and
obesity and having cancer in one of those other areas increases a woman's risk of ovarian
cancer. Women who have ovarian cancer also have a somewhat higher risk of developing
breast cancer.
Pregnancy and childbirth decrease the risk of ovarian cancer. Women who have never borne children are twice as likely to develop ovarian cancer as those who have. The use of oral contraceptives also appears to be mildly protective against ovarian cancer.
Signs and Symptoms
Ovarian cancer is often "silent" -- showing no obvious signs or symptoms until
it is in an advanced stage. The most common sign is an enlarged abdomen. Abnormal vaginal
bleeding is rarely seen.
Vague digestive disturbances may also signal the presence of ovarian cancer. These include stomach discomfort, gas, bloating, and constipation. An ovarian tumor pressing on the pelvic region could also cause a need to urinate frequently. Most often these are symptoms of less serious medical problems, but if they persist and cannot be otherwise accounted for, they may indicate the need for a thorough checkup.
Diagnosis of Ovarian Cancer
A screening exam that can detect ovarian cancer in women who do not have symptoms is not
currently available. The Pap test, so effective in detecting cervical cancer, does not
reveal ovarian cancer.
As part of its general guidelines for the early detection of cancer in women without symptoms, the American Cancer Society recommends that all women over 40 should have a cancer-related checkup each year. The examination should include a detailed health history. To evaluate the patient properly, the physician will need to know any family history of ovarian cancer, or endometrial cancer. Any persistent digestive or urinary irregularities should be brought to the attention of the physician.
Complete pelvic and rectal examinations are done to look for any abnormalities and palpate, or feel, the ovaries to determine if they are enlarged.
The physician may consider it necessary to view the ovaries themselves. A small cut is made in the abdomen, to permit the laparoscope, a lighted instrument, to be inserted. If suspicious for cancer, further abdominal surgery may be needed for proper diagnosis and treatment. During this procedure, known as a laparotomy, a biopsy is performed. This is the surgical removal of a small piece of tissue for microscopic examination to determine if cancer cells are present.
Additional tests may be done to determine the extent of the disease. Since ovarian cancer often spreads to the lungs, a chest x-ray may be ordered. Ultrasound, which uses high frequency sound waves to produce images of internal structures, may also be done, along with Computerized Axial Tomography (CAT Scan), a three-dimensional x-ray, and Magnetic Resonance Imaging (MRI), which uses electromagnets, rather than x-rays to produce cross-sectional views of areas of the body.
If necessary, other organs may also be evaluated by means of lymphography, a barium enema of the colon, radionuclide scan of the liver, and intravenous pyelogram of the kidneys, ureters, and bladder. For these procedures, the patient is given a substance that shows up clearly in those organs when x-rays. The rectum and lower colon may be inspected through a sigmoidoscope, a flexible lighted instrument, and bladder through a cystoscope.
Treatment of Ovarian Cancer
Ovarian cancer is almost always first treated by surgery. Chemotherapy and/or radiation
may also be used.
Surgery -- Treatment usually involves the removal of both ovaries (oophorectomy), both fallopian tubes (salpingectomy), and the uterus (hysterectomy). The omentum, the fold of fat tissue attached to the abdomen, is sometimes also removed (omentectomy). If other nearby organs, such as the bowel and the bladder, are affected, more extensive surgery may be required to remove as much of the cancer as possible and so improve the effectiveness of later treatment.
When the cancer is limited to one ovary and is still in an early stage of development, only that ovary may be removed, particularly in younger women still interested in having children.
Chemotherapy --
The anticancer drugs used in chemotherapy produce more extensive damage to cancer cells
than normal cells and the physician must maintain a delicate balance of dose and
frequency--giving enough chemotherapy to kill cancer cells, but not so much as to destroy
healthy cells. Dividing cells, both normal and cancerous, are most vulnerable to
chemotherapeutic agents.
For ovarian cancers, combination chemotherapy is usually more effective than treatment with a single drug. The most commonly used drugs are cisplatin, doxorubicin, and cyclophosphamide. Although it is not yet known for certain whether chemotherapy increases overall five-year survival rates, it has been shown to lengthen and improve the quality of survival time for some patients.
Advances in antibiotics and patient monitoring and the use of hyeralimentation (the intravenous administration of nutrients), have made it possible to give more aggressive treatments, Newer routes of administering combination chemotherapy are also being tested. Among them is intraperitoneal chemotherapy, injecting the drugs through catheters into the membrane that lines the abdominal cavity, so that the area is "bathed" in drugs. If the approach is planned, the surgeon should be prepared to plan the catheters a the time the ovaries and other organs are removed.
Common side effects of chemotherapy include nausea and vomiting, hair loss, anemia, reduced ability of the blood to clot, and an increased likelihood of developing infections and mouth sores. Women can expect regrowth of hair and the disappearance of most other side effects once treatment is stopped. In addition, nausea and vomiting can often be controlled quite effectively during treatment. Since individuals tolerate treatment differently, the side effects vary. Any unexpected side effects should be discussed with a physician.
Radiation -- The goal of radiation therapy is to destroy cancer cells by injuring their ability to divide, while minimizing the damage to surrounding tissue. Radiation therapy for ovarian cancer has been largely replaced by chemotherapy, but is still used selectively. It may be beamed at the tumor from an outside source, such as an x-ray machine, or emitted from radioactive substances, such as P32 injected directly into the abdomen. In some cases, radiation is directed at the entire abdomen and pelvis.
Side effects include skin reactions, nausea and vomiting, and a feeling of tiredness. They subside when treatment is stopped.
Follow-up Treatment Care
Women treated for ovarian cancer should have periodic follow-up exams. The frequency of
the exams and exact tests to be included vary according to the individual. If symptoms
such as bloating, nausea, vomiting, constipation, or weight loss occur, a woman should
notify her physician promptly.
A new blood test is proving very useful in monitoring the health of women treated for ovarian cancer. A substance has been developed that reacts with an antigen, CA 125. An antigen is a foreign agent that stimulates the formation of antibodies and CA 125 is found in the blood serum of most women with epithelial type ovarian cancer. The reaction with the antigen shows whether levels of CA 125 are rising, indicating the cancer is growing, or falling, indicating the disease is regressing.
If a woman is thought to have a complete response to treatment, meaning there is no further evidence of disease after surgery, chemotherapy, and/or radiation, a second-look operation may be considered to definitely determine if the patient is indeed cured. If so, no further treatment would be warranted at that time, although the woman should continue to have follow-up exams for several years.
Prognosis
When ovarian cancer is diagnosed and treated early, 85 percent of those patiens live five
years or longer. Since the symptoms of ovarian cancer are either vague or lacking and
since a simple screening test does not exist, it is usually not detected early. When
diagnosed in an advanced stage, the survival rate falls to 23 percent. The overall
five-year survival rate is 38 percent.
Hope For The Future
The real hope for the future lies in earlier detection. Researchers are now trying to
identify tumor markers, substances in the blood or urine that signal the presence of
cancer before symptoms develop, while the chances for cure are the highest. Cancer
specialists worldwide are also working to develop new, more effective treatments and to
improve the ways current treatments and to improve the ways current treatments are
administered.
Monoclonal antibodies, substances designed to seek out chosen targets on cancer cells, could prove useful in diagnosing ovarian cancer and delivering drugs directly to the tumor. Although originally derived from human cells, monoclonal antibodies can be mass-produced in the laboratory.
Know Cancer's Seven Warning Signals
If you have a warning signal, see your doctor! The University of Texas MD Anderson Cancer Center has more information: http://www.mdanderson.org/diseases/ovarian/
Last Update: 08/21/2007