Ovarian cancer begins when normal cells in an ovary change and grow uncontrollably, forming a mass, or tumor. The tumor can be benign (noncancerous) or malignant (cancerous).
An ovarian cyst, which forms on the surface of the ovary, is different than a noncancerous tumor and usually goes away without treatment. An ovarian cyst is not cancerous.
Ovarian epithelial cancer is the most common type of ovarian cancer. It begins in the tissue that covers the ovaries. (Although new evidence suggests at least some of ovarian cancer actually begins in special cells in the fallopian tube.)
The information here is only about ovarian epithelial cancer, not about ovarian germ cell tumors or other types of ovarian cancer. To find out more about all types of ovarian cancer, please visit the National Cancer Institute website, or come talk to us, your cancer care team at Willamette Valley Cancer Institute and Research Center, about your individual situation.