What Is Ovarian Cancer?
Ovarian cancer is cancer that involves primarily the ovaries, the female reproductive organs that produce eggs. A similar cancer can also start on the fallopian tube or the peritoneum, the inner lining of the abdomen, and the fallopian tube may actually be the initial source for ovarian cancer in most cases.
Ovarian cancer is the seventh most common cancer among women and causes more deaths than any other type of female reproductive cancer. It is the fifth highest cause of all cancer deaths in women. The cause of ovarian cancer is not yet known.
Many ovarian masses are not ovarian cancer, but if a mass is worrisome on imaging or persists for an extended period of time, it requires evaluation.
What Are the Risk Factors for Ovarian Cancer?
All women are at risk of developing ovarian cancer with a lifetime risk of 1/70. Most ovarian cancers are found in women older than 60 and are more often found in white than African-American women. Some factors that may increase the risk of ovarian cancer include:
- Family or personal history: Women with a mother, daughter or sister with ovarian cancer have a higher risk; women with a family or personal history of breast, uterus, colon, or rectum cancer also have increased risk. Known family genetic mutations such as BRCA or Lynch syndromes increase the risk of ovarian cancer
- Having children late or not having children
What Are the Symptoms of Ovarian Cancer?
The symptoms of ovarian cancer are vague and often go unnoticed until the disease has spread beyond the ovaries. More than 70 percent of patients are not diagnosed until ovarian cancer is at an advanced stage. Ovarian cancer may spread even before symptoms occur.
Women who have any of the following symptoms on a daily basis for more than two to three weeks should see a medical provider immediately, particularly if they have not had these problems before:
- Pelvic or abdominal pain
- Difficulty eating or feeling full quickly
- Change in bowel habits
- Urinary urgency or frequency
- Sudden unusual weight loss or weight gain
How Is Ovarian Cancer Diagnosed?
Diagnosis starts with a thorough medical history and physical exam, including a pelvic exam.
Additional testing may include:
- Imaging tests - such as ultrasound, computed tomography (CT) scan and/or possibly MRI to identify and characterize tumors and to determine if cancer has spread to other areas
- Blood tests - to measure, among other things, levels of CA-125, a protein in the blood that may be higher than normal in women with ovarian cancer
- Biopsy - the removal of a tissue sample or fluid for examination under a microscope to see if cancer cells are present. Masses confined to the ovary generally cannot be biopsied and must be removed surgically for diagnosis.
- Surgical procedures - such as a laparotomy (large surgical incision) or laparoscopy (surgery through small incisions with a camera) to view and/or remove the ovaries and other pelvic organs, do a biopsy, or determine whether the cancer has spread
Types of Ovarian Cancer
Ovarian cancer is sometimes limited only to the ovaries, but often, ovarian cancer metastasizes or spreads to other parts of the body. There are three main categories of ovarian cancer:
Epithelial. This is the most common type of ovarian cancer and includes about 90 percent of diagnosed cases. The tumor may resemble one of several types of epithelial tissue that lines the insides of nearby structures (such as the fallopian tube, uterus or cervix) and is often diagnosed in older patients. Cancers associated with genetic mutations such as BRCA mutations tend to be epithelial. The risk of epithelial ovarian cancer increases with age with the average patient age around 63.
Germ cell. Germ cell tumors occur in only five percent of ovarian cancer cases and start in the egg-producing cells of the ovaries. They can occur at any age but are more commonly found in patients under 30 years old.
Sex cord stromal. These tumors are also rare and occur in only five percent of ovarian cancers. They start from the ovarian stromal tissue (supporting cells of the ovary) and may be associated with increased hormone levels, including estrogen, progesterone, and testosterone. Sex cord stromal tumors occur in young and older women.
Fallopian tube cancer. The fallopian tube may actually be the initial source of most "ovarian" cancers. Pre-cancerous cells are sometimes found in the tube and the cancer is occasionally found only in the tube. Primary peritoneal cancer is reported when there is serous carcinoma found with no involvement of the tubes or ovaries. The symptoms and treatment are similar to ovarian cancer.
Because many “ovarian” cancers are thought to originate in the fallopian tube, women undergoing a hysterectomy or sterilization are now frequently encouraged to have their fallopian tubes removed even if they are keeping their ovaries. The concept of the fallopian tube as the source of most ovarian cancers is recent, so there is not clear evidence to support this practice. Because ovarian cancer is difficult to cure, many providers encourage their patients to remove the entire tube in spite of the lack of data.
Can Ovarian Cancer Be Prevented?
Unfortunately, no screening tests for ovarian cancer have been shown to decrease the risk of ovarian cancer or to detect it in a pre-cancerous state. However, patients who have a strong family history of breast or ovarian cancer or who may have a genetic predisposition to ovarian cancer should be seen by a gynecologic oncologist and followed closely, and consider having her ovaries removed after finishing her family. While it is not yet known how to prevent ovarian cancer, research suggests women may be able to reduce their risk through:
- Birth control pills - taken for five years or more; however, oral contraceptives may slightly increase the risk of developing breast cancer, particularly in women over the age of 40, so weigh the risks and benefits with your gynecologist.
- Pregnancy and breast feeding
- Genetic testing and surgical prevention - Women with a family or personal history of certain cancers may consider genetic testing to determine if they carry genetic mutations that place them at higher risk.*
*In high-risk cases, or when a hysterectomy is being performed for other medical reasons, removal of both ovaries and fallopian tubes may be considered.
How is ovarian cancer treated?
Treatment depends on the individual patient and their cancer but typically involves a combination of therapies, including:
- Surgery - removes cancerous tissues, that may include the ovaries, uterus, omentum (fatty apron coming off the colon) and sometimes lymph nodes near the tumor to determine if it has spread. Other involved tissues may also be removed. Surgery is frequently preceded or followed by chemotherapy.
- Chemotherapy. The use of medications, typically given intravenously (through a vein), to destroy cancer cells.
- HIPEC. Some ovarian cancer patients are candidates for HIPEC, or heated intraperitoneal chemotherapy, administered during their cancer surgery while the patient is still under anesthesia.