Cancer of the ovary is a disease in which cancer (malignant) cells are found in a women’s ovary. Approximately 23,000 women in the United States are diagnosed with the disease each year. The ovary is a small organ in the pelvis that makes female hormones and holds egg cells which, when fertilized can developed into a baby.
How Does it Begin?
Ovarian cancer begins when cells in the ovary lose the normal constraints upon their growth. The ovaries are two small organs situated on either side of the uterus (womb), deep within the pelvic cavity. The ovaries produce female hormones and store egg cells, which when fertilized by a sperm cell can result in pregnancy. Cancer of the ovary is diagnosed in nearly 20,200 women in the United States each year. Ovarian cancer is the fifth-leading cause of cancer death among American women and has the highest death rate of all gynecological cancers. An estimated one in 55 women who reach ages 75 to 79 will develop ovarian cancer during her lifetime.
The average age of a woman diagnosed with ovarian cancer is 61. According to statistics made available by the National Institutes of Health, in the past decade there has been a 30 percent increase in the number of cases of ovarian cancer and an 18 percent increase in the number of deaths attributable to ovarian cancer.
How does ovarian cancer develop?
The cause of ovarian cancer is not yet understood. Several theories have been proposed to explain how the disease occurs. According to one theory, repeated uninterrupted ovulation causes the surfaces of the ovaries to undergo cellular changes that lead to the development of cancer. Another theory surmises that increased levels of pituitary hormones, not cellular changes, are responsible for the cancer. Still another theory speculates that alterations in blood flow to the ovaries play a role in cancer development.
Diagnosis and Treatment
The only definitive way to diagnose ovarian cancer is through the microscopic examination of a sample of ovarian tissue. This is called a biopsy. If ovarian cancer is suspected, a surgeon (gynecologic oncologist) does an operation to remove the entire ovary (oophorectomy), since cutting into a cancerous ovary could cause the release of cancerous cells to other parts of the body.
If the biopsy at or during surgery proves malignant (cancerous), a more extensive oncologic surgery usually is performed. This is usually performed at the same time following the biopsy taken early in the surgery and sent to the pathologist for analysis while surgery continues. If the gynecologic oncologist is available, he or she will assist in the surgery. Surgery for ovarian cancer most often involves the removal of the ovaries, uterus and fallopian tubes. In some cases, when the tumor is slow-growing and confined to the ovary, the surgeon may remove only the affected ovary in an effort to preserve a woman’s fertility for young women.
During surgery, samples of nearby lymph nodes and abdominal tissues and fluid (omental cake) also are removed, as well as biopsies taken of the diaphragm above the liver. Abdomen (peritoneal) washings are also sent to the pathologist to determine if there are cancer cells present. This is called surgical staging, and is performed to determine how invasive the cancer has become and what follow-up treatments should be initiated. Surgical staging takes into account the size of the tumor, whether it has spread to surrounding lymph nodes, and whether other organs have been affected by the tumor. Additionally, the malignant tissue is examined microscopically to determine how aggressive it is and other characteristics that may affect a woman’s overall survival rate. All of this information is compiled before a treatment plan is devised.
Determining which treatment to pursue for ovarian cancer is a joint decision that must be made by the physician and the patient after pathologic review. Receiving a diagnosis of cancer is an overwhelming experience. Making treatment decisions also can be confusing for women who are not familiar with the disease. Write down questions that you want to discuss, or you may wish to have another family member accompany you to the doctor’s office. Don’t be afraid to get a second opinion from a gynecologic oncologist before committing to a particular course of treatment.
Treatment options for ovarian cancer.
Treatment for ovarian cancer may involve surgery, chemotherapy or radiation therapy or a combination of these.
Surgery. Surgery is usually the initial treatment for ovarian cancer. Because tissue samples are needed to make the diagnosis of ovarian cancer, a laparotomy (incision into the abdomen) will be performed. If the surgeon determines that the cancer has spread, a procedure known as debulking will most likely be attempted. Tumor debulking reduces the amount of cancer because it may be impossible to completely remove all of it. The remaining cancer is treated later with chemotherapy or occasionally radiation. In the earliest stages of ovarian cancer, surgery may be able to completely remove the tumor and additional therapies may not be needed. All efforts for complete staging and debulking bowel resections (often a four to seven hour operation) are made because maximal debulking leads to a better chance for a cure with chemotherapy.
Chemotherapy. Chemotherapy involves the administration of drugs (either by mouth or intravenous injection) to destroy cancer cells. Because these drugs not only affect the cancer cells but also target healthy cells, they may produce unwanted side effects. Medications are available to help control the side effects associated with chemotherapy. Your physician will discuss with you which chemotherapy drugs are most likely to eradicate your remaining cancer.
Chemotherapy is generally administered in cycles, meaning that you will receive the drugs for a specified period of time and then you will be given another period of time to recover. Chemotherapy may be administered as an outpatient or it may require an overnight hospital stay. Clinical trials, aimed at finding new ways to fight ovarian cancer, are studying the administration of chemotherapy directly into the abdomen (intraperitoneal chemotherapy). It is anticipated that this approach will fight the cancer directly.
Some of the chemotherapy drugs commonly used to treat ovarian cancer include cisplatin (Platinum®), paclitaxel (Taxol®) carboplatin (Paraplatin®), docetaxel (Taxotere®) gemcitabine (Gemzar®) liposome doxorubicin, topotecan (Hycamtin®) and cyclophosphamide (Cytoxan®, Neosar®). The response rate is high, and the patient is carefully followed with CA 125 tumor markers and periodic CT scans.
CA 125 is made mostly by ovarian cancer cells. Many women with ovarian cancer have high CA 125 levels. CA 125 is used mostly to manage treatment for ovarian cancer. In women with ovarian cancer being treated with chemotherapy, a falling CA 125 level generally shows the cancer is responding to treatment. Increasing CA 125 levels during or after treatment, on the other hand, may suggest the cancer is not responding to therapy or that some cancer cells remain in the body.
Radiation therapy. Radiation therapy involves the delivery of high-energy X-rays to specific cancer sites to stop their growth. In ovarian cancer, radiation therapy can be delivered externally, or from radioactive implants that are placed into the body near the tumor site. External radiation treatments are usually given five days each week, for a period of about five weeks, for an outpatient. Internal radiation treatments require hospitalization. Since chemotherapy has been successful, radiation therapy is less commonly used.
Because the treatment for ovarian cancer is rapidly evolving, all women diagnosed with this disease should be considered for clinical trials. Many clinical trials for ovarian cancer are presently ongoing. They are studying new drugs, newer drug dosing and scheduling, and various other ways of combining treatments. The National Cancer Institute is a good source for learning about clinical trials.