What is Ovarian Cancer?

Ovarian cancer is a disease in which malignant, or cancerous cells are found in the tissues of the ovary. The ovary is a reproductive organ about the size of an almond, found only in women in their lower abdomen. Ovaries make the female reproductive hormones, estrogen and progesterone, and also make eggs, one of which is released monthly through the fallopian tubes into the uterus. One ovary is on each side of the uterus. [See illustration.] When a woman undergoes menopause ovaries stop releasing eggs and produce much less hormones.

Normally, cells, the building blocks of tissue and organs in the body, divide and grow to form new cells when the body needs them. Sometimes, the process goes haywire with new cells growing uncontrollably and creating a tumor, which can be benign (or non-cancerous) or malignant (cancerous).

While benign tumors do not invade adjacent tissues, malignant tumors do invade adjacent tissue and cells from malignant tumors also can move to distant parts of the body, breaking away from the primary tumor, in what is called metastasis. These metastatic cells invade other organs and damage them, which can be life-threatening.

Ovarian cysts, or closed sacs, may be found on the surface of the ovary or inside it. The sac can be fluid-filled, have solid tissue inside, or both. While most ovarian cysts are benign, some contain cancerous tissue.

Cancerous ovarian cells from the primary tumor can invade the nearby fallopian tubes and the other ovary. Ovarian cancer cells also can shed into the abdominal cavity and cause new tumors on the surface of nearby organs, such as the intestines; or on tissues, such as the peritoneum, a tissue that lines the abdominal and pelvic cavities. Further, malignant cancer cells can enter the blood stream and the lymphatic system–a network of vessels that carries lymph, a special fluid in the body, and includes lymph nodes and other organs. When cancer moves from its site of origin to another part of the body, the new tumor has the same kind of abnormal cells and same name as the original kind of tumor. For example, if ovarian cancer spreads to the liver, those cancer cells in the liver are actually ovarian cancer cells. In this case, the disease is called metastatic ovarian cancer, not liver cancer.

Ovarian cancer is staged depending on how far the cancer has spread. Ovarian cancer is also graded depending on how the tissue appears under the microscope. The higher the grade, the more likely the cancer will spread. Grade 3 looks less like ovarian tissue compared to lower grade cancer tissue, Grade 1, which looks more like ovarian tissue.