Introduction to Ovarian Cancer
The ovaries are located in the pelvis, one each side of the uterus. Each of these female reproductive organs is the size and shape of an almond. During each monthly menstrual cycle, one ovary releases an egg. The egg travels through the fallopian tube to the uterus.
Most ovarian cancers are epithelial, originating in the lining 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.
The cause of ovarian cancer is unknown. Among women in the U.S., cancer of the ovary is the fourth most common cancer and the leading cause of death from gynecologic cancer.
The incidence of ovarian cancer increases steadily with age, with most cases found in women 55 to 75 years of age. It occurs with equal frequency in each of the two ovaries.
Early detection of ovarian cancer is difficult because cancer that is limited to the ovary usually does not cause symptoms. An ovarian tumor can grow for some time without causing pressure, pain, or other problems.
When symptoms do appear, they are generally so vague that they are often ignored. The most common signs are abdominal swelling or bloating, lower abdominal discomfort, a feeling of discomfort, a feeling of fullness even after a light meal, and loss of appetite. Other complaints may include gas, indigestion, nausea, and weight loss.
As the cancer grows it may affect nearby organs such as the bladder and large bowel, causing frequent urination and constipation. Occasionally, vaginal bleeding can be a symptom of ovarian cancer.
To diagnosis ovarian cancer, the doctor asks about the woman's personal and family medical history and does a physical exam, including a pelvic exam and pap smear. If there is a history of ovarian, breast, colorectal, uterine or bladder cancer a woman should be evaluated with two tests: CA 125 (a blood test that detects a protein sometimes produced by ovarian tumors); and transvaginal ultrasound (TVS).
The doctor may also order a CT scan (cross-sectional x-rays of the body and imagined by a computer), lower GI series or barium enema (x-rays of the lower bowel) or intravenous pyelogram (IVP). IVP is a test in which x-rays are taken of the kidneys, ureters and bladder after an injection of a dye.
If these tests indicate a cancerous situation the next step, for positive identification, is a biopsy of the ovaries to obtain tissue samples for microscopic examination.
Ovarian cancer may be treated with surgery, chemotherapy, or radiation therapy. The treating doctor may use just one method or combine them. Surgery is part of the treatment for almost all patients with ovarian cancer. Chemotherapy - the use of drugs to kill cancer cells - is generally given when there are signs that the cancer has spread, or when the entire tumor cannot be removed at the time of surgery. Radiation therapy may be used in addition to surgery to kill cancer cells that may remain in the pelvic area.
Surgery for ovarian cancer includes removal of the ovaries, the uterus, and the fallopian tubes. However, if a woman has a very early, slow-growing tumor and wants to have a child, the doctor may decide to remove only the affected ovary.
When the cancer has spread to other organs in the abdomen, doctors try to remove as much of the cancer as possible.This leaves a smaller amount to be treated by chemotherapy and/or radiation therapy.
Chemotherapy for ovarian cancer uses a combination of several drugs. Chemotherapy is usually given in cycles: a treatment period followed by a rest period, then another treatment and rest period, and so on.
Chemotherapy is called systemic therapy because the drugs travel all through the body in the bloodstream. Most women receive chemotherapy as an outpatient at the hospital, at the doctor's office, or at home. Depending on which drugs are used or how they are given, however, a patient may need to stay in the hospital for a short while.
The most promising chemotherapy drug is Taxol. Taxol has now been shown to have increased survival of women with advanced ovarian cancer by more than 50 percent when combined with a standard chemotherapy. While some side effects of Taxol, including hair loss and a low white blood cell count, were more severe than for standard therapy, Taxol is generally more acceptable to patients.
Radiation therapy uses high-energy rays to damage cancer cells and stop them from growing. Like surgery, radiation therapy is local therapy; it affects only the cells in the treated area. The patient goes to the hospital or clinic each day for radiation treatments. Usually, treatments are given 5 days a week for 5 to 6 weeks.
Another type of radiation therapy is intraperitoneal radiation. It may be used to put radioactive material as close as possible to the cancer. Radioactive material is placed directly into the pelvis and abdomen through a thin tube. The patient's position is changed frequently to allow the liquid to coat all the organs in the abdomen and pelvis.
Doctors are also studying the use of intraperitoneal chemotherapy. This newer approach places anticancer drugs directly in the abdomen and pelvis through a thin tube. As in intraperitoneal radiation treatment, the woman's position is changed frequently to allow the drugs to spread throughout the abdomen and pelvis. In this way, more drugs reach the cancer directly.