What is cancer?

Cancer is when cells in the body change and grow out of control. To help you understand what happens when you have cancer, let's look at how your body works normally. Your body is made up of tiny building blocks called cells. Normal cells grow when your body needs them and die when your body does not need them any longer.

Cancer is made up of abnormal cells that grow even though your body doesn't need them. In most cancers, the abnormal cells grow to form a lump or mass called a tumor. If cancer cells are in the body long enough, they can grow into (invade) nearby areas. They can even spread to other parts of the body (metastasis).

Understanding the ovaries

To understand where the tumor is, it may help to know more about how your ovaries work in your reproductive system:

• Ovaries. There are 2 of these. They produce hormones and eggs.

• Fallopian tubes. These are the tubes through which an egg travels from the ovaries to the uterus. There are 2 tubes, 1 leading from each ovary to the uterus.

• Uterus. This is the hollow, pear-shaped organ that holds a growing baby. It's also called the womb.

• Vagina. This is the passage that connects the uterus to the outside of your body. It's also called the birth canal.

Your ovaries are located on either side of the uterus, in your pelvis. Each month, one of the ovaries releases an egg. After the egg leaves the ovary, it goes down the fallopian tube. If the egg connects with a sperm, it’s fertilized and attaches to the wall of the uterus. There it grows to become a baby. If the egg isn’t fertilized, it leaves the body through the vagina along with the menstrual flow. The ovaries also make the hormones estrogen and progesterone. These control the development of certain parts of your body. These include the breasts, body shape, and body hair. These hormones also control your menstrual cycle.

At menopause, the ovaries stop releasing eggs. They also stop making certain hormones.

What is ovarian cancer?

Ovarian cancer is cancer that starts in your ovaries or at the end of the fallopian tubes next to an ovary. Only people with ovaries get this kind of cancer.

Many types of tumors can start growing in the ovaries. Some are benign. This means that they're not cancer. Benign tumors don’t spread but they can grow quite large and cause symptoms. They can usually be treated by removing 1 ovary or part of the ovary. Ovarian cancer is a malignant (cancerous) tumor. If a cancerous tumor isn’t treated, it can grow and spread to other parts of your body.

The ovary is made up of many layers of cells. Cancer can affect any one or all of these layers. These are the main types of ovarian cancer.

Epithelial ovarian cancer

This is by far the most common type of ovarian cancer. It starts in cells on the outer surface of the ovary. Many epithelial ovarian cancers start in the fallopian tube epithelial cells near the ovary or the lining of the inside of the belly (peritoneal) epithelial cells. Then they go to the surface of the ovary. There are several types of epithelial ovarian cancer. High-grade serous carcinoma is the most common subtype of epithelial ovarian cancer.

Germ cell ovarian cancer

This cancer starts in the cells that form eggs in the ovary. These rare tumors are most common in people with ovaries ages 10 to 29. There are different sub-types of germ cell tumors.

Stromal cell cancer

This cancer forms in the tissue that makes certain female hormones and holds the ovaries in place. This is also a very rare form of ovarian cancer.

Talk with your healthcare provider

If you have questions about ovarian cancer, talk with your healthcare provider. Your healthcare provider can help you understand more about this cancer.