It's not clear what causes ovarian cancer.

In general, cancer begins when healthy cells acquire a genetic mutation that turns normal cells into abnormal cells. Healthy cells grow and multiply at a set rate, eventually dying at a set time. Cancer cells grow and multiply out of control, and they don't die when they should.

As abnormal cells accumulate, they form a mass (tumor). Cancer cells invade nearby tissues and can break off from an initial tumor to spread elsewhere in the body (metastasize).

Types of ovarian cancer

The type of cell where the cancer begins determines the type of ovarian cancer you have. Ovarian cancer types include:

  • Cancer that begins in the cells on the outside of the ovaries. Called epithelial tumors, these cancers begin in the thin layer of tissue that covers the outside of the ovaries. Most ovarian cancers are epithelial tumors.
  • Cancer that begins in the egg-producing cells. Called germ cell tumors, these ovarian cancers tend to occur in younger women.
  • Cancer that begins in the hormone-producing cells. These cancers, called stromal tumors, begin in the ovarian tissue that produces the hormones estrogen, progesterone and testosterone.

The type of ovarian cancer you have helps determine your prognosis and treatment options.

Nov. 10, 2012