About Ovarian Cancer
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Ovarian cancer is a gynecologic cancer that originates in the ovaries. Women have two ovaries that produce ova (eggs) and are the main source of women’s female hormones, progesterone and estrogen. The ovaries are made up of three kinds of tissue:
- epithelial cells that cover the ovaries
- germ cells that make the ova inside of the ovary
- stromal cells that make most of the female hormones
Though ovarian cancer can start anywhere in the ovary, most ovarian cancers start in the epithelial cells and produce epithelial ovarian tumors. Ovarian cancer begins when normal ovarian cells begin to grow in an abnormal and uncontrolled manner, producing tumors.
Three similar cancers
There are two cancers that are similar to ovarian cancer in symptoms and treatment. They are fallopian tube cancer and primary peritoneal cancer. Fallopian tube cancer originates in the fallopian tubes (the tubes that connect the ovaries to the uterus), and primary peritoneal cancer is cancer of the peritoneum (the tissue covering the entire abdominal area and its organs).
Fallopian tube cancer treatment is similar to epithelial ovarian cancer. Symptoms are commonly abdominal pain and a vaginal leak. It occurs more frequently in women with a genetic predisposition. As researchers learn more about ovarian and fallopian tube cancers, they are finding that some cases of ovarian cancer may actually be fallopian tube cancer. Fortunately, for patients, the doctors who treat the cancers, the staging processes used and the treatments are the same.
Primary peritoneal cancer also occurs more frequently in women with a genetic predisposition, and it can occur in women who have had both their ovaries and fallopian tubes removed. Though there is a medical distinction between ovarian and primary peritoneal cancer, the treatments are very similar.
In all three cancers (ovarian, primary peritoneal and fallopian tube), the individual cancer cells look similar under the microscope (histology) and respond similarly to aggressive surgery and chemotherapy. Doctors at Northwestern Memorial consider them similarly, and the risk factors for all three cancers are similar. When we mention epithelial ovarian cancer or ovarian cancer, we are including all three of these cancers.
Once ovarian cancer is diagnosed, the grade and stage of the cancer will be determined.
- Grade refers to how aggressive individual cells look.
- Stage describes whether the cancer has spread and, if so, how much.
Are all ovarian tumors cancerous? No.
There are many types of ovarian tumors, and not all of them are cancerous. Many ovarian tumors turn out to be benign (non-cancerous) tumors. Tumors are considered cancerous when they can:
- Spread to other places (metastasize)
- Grow into surrounding tissues (invade)
- Return in the future, even after they’ve been removed (recur)
Types of ovarian tumors are:
- Benign epithelial tumors—they do not spread and don’t typically lead to serious illness
- Tumors of low malignant potential (LMP tumors)—also referred to as borderline tumors
- Epithelial ovarian cancers—they make up nearly 90 percent of all ovarian cancers, and the cancer cells are classified by grade, depending on how closely they resemble normal cells
- Germ cell tumors—originate in the germ cells of the ovaries. These tumors can happen in younger people and can be very curable
- Sex cord stromal tumors—originate in the sex cord stromal cells of the ovary and produce extra hormones that lead to symptoms
Borderline or LMP tumors are confusing to patients and doctors alike. Most often, they do not have cancerous behavior. However, a small percentage of these tumors will display features of cancer, such as spreading to other tissue or recurring in the future. Features of the tumor and the stage it is in can help your doctor describe the possible behavior of the tumor and treatment and follow-up options.
There are other forms of ovarian cancer and ovarian abnormalities. For more information about ovarian cancer, please refer to our health encyclopedia.
The ovarian cancer section was made possible by a generous grant from Bears Care.