Cancer is a disease in which abnormal cells in the body grow out of control and form a tumor. Ovarian cancer is a cancerous tumor that forms in the tissues of an ovary. The ovaries are a pair of female reproductive glands that make eggs and female hormones.

There are a few different types of ovarian cancer. The most common type is epithelial cancer. It begins in the cells that cover the ovary.

There are also two related types of epithelial cancer that can spread to the ovaries:

• Fallopian tube cancer forms in the tissue lining a fallopian tube. The fallopian tubes are a pair of long, slender tubes on each side of the uterus. The uterus is the female reproductive organ where a baby grows during pregnancy.
• Primary peritoneal cancer forms in the tissue lining the peritoneum. Your peritoneum is a tissue lining that covers the organs in the abdomen (belly).

These two cancers are similar to ovarian cancer, and they have the same treatments. So some medical experts also consider those two types as ovarian cancer.

Some other rarer types of ovarian cancer are malignant germ cell tumors and stromal tumors.

Ovarian cancer happens when there are changes (mutations) in the genetic material (DNA). Often, the exact cause of these genetic changes is unknown.

Most ovarian cancers are caused by genetic changes that happen during your lifetime. But sometimes these genetic changes are inherited, meaning that you are born with them. Ovarian cancer that is caused by inherited genetic changes is called hereditary ovarian cancer.

There are also certain genetic changes that can raise your risk of ovarian cancer, including changes called BRCA1 and BRCA2. These two changes also raise your risk of breast and other cancers.

Besides genetics, your lifestyle and the environment can affect your risk of ovarian cancer.

Certain people are more likely to develop ovarian cancer. They include those who:

• Have a family history of ovarian cancer in a mother, daughter, or sister
• Have inherited changes in the BRCA1 or BRCA2 genes.
• Have certain other genetic conditions, such as Lynch syndrome
• Have endometriosis
• Took hormone replacement therapy
• Are overweight or have obesity
• Are tall
• Are older, especially those who have gone through menopause

Ovarian cancer may not cause early signs or symptoms. By the time you do have signs or symptoms, the cancer is often advanced.

The signs and symptoms may include:

• Pain, swelling, or a feeling of pressure in the abdomen or pelvis
• Sudden or frequent urge to urinate (pee)
• Trouble eating or feeling full
• A lump in the pelvic area
• Gastrointestinal problems, such as gas, bloating, or constipation

To find out if you have ovarian cancer, your health care provider:

• Will ask about your medical history, including your symptoms
• Will ask about your family health history, including relatives who have had ovarian cancer
• Will do a physical exam, including a pelvic exam
• Will likely do imaging tests
• May do blood tests such as a CA-125 blood test

Often the only way to know for sure that you have ovarian cancer is by having a biopsy of the tissue. A biopsy is done during surgery to remove the tumor.

Treatments for ovarian cancer may include:

• Surgery to remove as much of the cancer as possible
• Chemotherapy
• Targeted therapy, which uses drugs or other substances that attack specific cancer cells with less harm to normal cells

Your provider may suggest that you have genetic testing to look for the gene changes that raise the risk for ovarian cancer. Knowing whether or not you have the gene change may help your provider decide on your treatment plan.

NIH: National Cancer Institute