Ovarian cancer

Ovarian cancer is a form of cancerous tumor affecting one or both ovaries. The disease, most of times, develops from the group of cells which cover the outer cellular surface of the ovaries, and can remain completely asymptomatic for years – please see ovarian cancer symptoms for info.

There are different types of malignant tumor that can affect the ovary, but the most common form is the epithelial ovarian carcinoma, accounting for 90-95% of cases. The other forms such as ovarian germ cell tumors and borderline ovarian tumors (BOTs) are rare and required specific treatment. Please see ovarian cancer treatment

The incidence of ovarian cancer is higher in Europe and the United States compared to Japan and the less industrialized countries. The reasons are not well known to scientists.

The Ovary (Ovaries)


The ovaries are part of the female reproductive system. These are two small oval organs located on each side of the uterus (or womb), near the end of the fallopian tubes. They play many functions such as producing and releasing eggs (ova); as well as producing female hormones: estrogens and progesterone.

The ovaries are composed of different types of cells: epithelial cells, which form the outer layer of the ovary (epithelium); stromal cells, forming the connective tissue that holds the components of the ovary together; and the germ cells (also called gametes or sex cells), which are the reproductive cells. These groups of cells work together in harmony to allow the ovaries to play its functions.

But some sometimes a group of cells of an ovary may undergo changes that make them to behave or grow abnormally. These changes can cause the development of non-cancerous or benign tumors, such as cysts. They can also cause the formation of other non-cancerous tumors that are not life-threatening.

Non-Cancerous Tumors of the Ovaries

For example, Changes in epithelial cells can cause the occurrence of adenoma serous (an abnormal growth of tissue from the epithelial tissue) or mucinous adenoma (an abnormal growth of tissue arising from the epithelium of the ovary); they are benign tumors. Modified stromal cells can in turn lead to the development of these non-cancerous tumors: thecoma, also known as theca cell tumors, an ovarian benign tumor from the theca cells of the ovaries; fibroma, also called sex-cord stromal cell tumors of the ovary, a solid tumor that forms in the cells of the sex cord of the ovaries. Changes in germ cells can cause the development of non-cancerous germ cell tumors (GCT).

Cancerous Tumors of the Ovaries

In some cases, however, the alteration in the ovary cells can transform into ovarian cancer. In this case, the condition is more serious and requires more advanced treatment. It is also important to note that ovarian cancer symptoms can be mistakenly taken for non-cancerous conditions and neglected.

In general, there are three main types of ovarian cancer; each one is originating in a different type of cells:

  • Ovarian Epithelial Cancers – malignant tumors that arise in the epithelial cells are called epithelial ovarian carcinomas. The serous carcinoma is the most common type of epithelial cancer of the ovary. Ovarian epithelial cancer is the most common form of ovarian malignancies.
  • Ovarian Stromal Cancers – ovarian stromal tumors develop in the cells of connective tissue which hold the ovaries together and those that manufacture estrogen and progesterone. The granulosa cell tumors are the most common type of stromal tumors.
  • Germ Cell Tumors – these are rare cancerous tumors that form in the germ cells; dysgerminoma and ovarian yolk sac tumor for examples.

Extraovarian primary peritoneal carcinoma (EOPPC) is another rare type of ovarian cancer that can also occur. This tumor can grow in the peritoneum, the membrane that lines the walls of the abdomen and pelvis. It is similar to epithelial ovarian carcinoma, except that there is little or no cancer at all in the ovaries, and its origin is not really known.

Ovarian cancer diagnosis is a serious health concern. The fact that the tumor is often diagnosed late, it is generally a poor prognosis condition, causing more deaths than any other cancer of the female reproductive system, according to the American Cancer Society (ACS). The tumor may develop slowly without clinical signs until it becomes very advanced.

Treatment is based on total surgical removal, in combination with chemotherapy to reduce the risk of recurrence. When the cancer is very advanced, chemotherapy can be used to improve the patients’ quality of life and increase the duration of survival. Please see ovarian cancer treatmentfor information.


  1. Hennessy BT, Coleman RL, Markman M, « Ovarian cancer » [ archiveLancet 2009;374:1371-1382.
  2. Collaborative Group on Epidemiological Studies of Ovarian Cancer, « Ovarian cancer and oral contraceptives: collaborative reanalysis of data from 45 epidemiological studies including 23257 women with ovarian cancer and 87303 controls » [ archiveLancet 2008;371:303-314.
  3. American Cancer Society: Abnout Ovarian cancer/
  4. Lee-Jones, L ; Ovary: Epithelial tumors; Atlas Genet Cytogenet Oncol Haematol. 2004;8(2):115-133 – Free journal version : [ pdf ]   [ DOI ]
  5. On line version : http://AtlasGeneticsOncology.org/Tumors/OvaryEpithTumID5230.html

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