What is ovarian cancer?
Ovarian cancer begins in the ovaries. Women have 2 ovaries, one on each side of the uterus in the pelvis, as shown in the picture below. The ovaries produce eggs (called ova). They are also the main source of a woman’s female hormones, estrogen and progesterone. The eggs travel through the fallopian tubes to the uterus. Here they may be fertilized and develop into a fetus.
The ovaries are made of 3 main kinds of tissue:
- Epithelial cells cover the ovary
- Germ cells make eggs (ova) inside of the ovary
- Stromal cells hold the ovary together and make most of the female hormones (estrogen and progesterone)
Types of ovarian tumors
Many types of tumors can start in the ovaries. Some are benign (not cancer) and never spread beyond the ovary. Women with these types of tumors can be treated by taking out either the ovary or the part of the ovary that has the tumor. Other types of tumors are cancerous (or malignant) and can spread to other parts of the body. They need more treatment which we will explain later.
As a rule, tumors in the ovary are named for the kinds of cells the tumor started from and whether the tumor is benign or cancerous. There are 3 main types of tumors:
Epithelial tumors: These tumors start from the cells that cover the outer surface of the ovary. Most ovarian tumors are epithelial cell tumors.
Germ cell tumors: These start from the cells that produce the eggs.
Stromal tumors: These start from cells that hold the ovary together and make the female hormones.
The information in this document is about the most common kind of ovarian cancer, invasive epithelial ovarian carcinoma. Be sure to ask your doctor what type of ovarian cancer you have. If you need information about ovarian stromal tumors and ovarian germ cell tumors, please see our detailed document, Ovarian Cancer.
Epithelial ovarian tumors
Epithelial ovarian tumors are further divided into 3 sub-groups: benign, low malignant potential, and malignant.
Benign epithelial tumors
These tumors are not cancer. They don’t spread and usually do not lead to serious illness.
Tumors of low malignant potential (LMP tumors)
These tumors do not clearly appear to be cancer when looked at under the microscope. They are also known as borderline epithelial ovarian cancer. They tend to affect women at a younger age than other ovarian cancers. They grow and spread slowly and are less life-threatening than most ovarian cancers.
Malignant epithelial ovarian tumors
These are the most common ovarian cancer. When someone says they have ovarian cancer, they usually mean this kind. These cancers can also be divided into different types based on certain features that can be seen under a microscope.
Last Medical Review: 04/22/2013
Last Revised: 02/06/2014