What is ovarian cancer?
Ovarian cancer is a disease in which cells in the ovaries grow out of control and form tumors. A tumor can be cancerous or benign. A benign tumor can grow and will not spread, but a cancerous tumor is malignant, meaning it can grow and spread to other parts of the body.
Women’s risk of getting ovarian cancer during their lifetime is about 1 in 78. About 57% of patients are diagnosed when the cancer has spread to a distant part of the body.
Ovarian cancer risk can run in families and can be passed down from the mother and/or father’s side. About 20 to 25% of women with ovarian cancer have a genetic predisposition for developing the disease. Risk factors include inherent genetic mutations in either of the two genes: breast cancer gene 1 (BRCA1) and breast cancer gene 2 (BRCA2). Inherited mutations of BRCA1 and BRCA2 account for approximately 10 to 15% of all cases of ovarian cancer.
You can read more about these kinds of cancers in the Is Cancer Genetic? article or learn more about testing for inherited cancer in the Genetic Testing for Cancer article.
19,710
estimated new cases of ovarian cancer in the US in 2023
What are the types of ovarian cancer?
Ovaries are mainly made up of 3 kinds of cells that can develop into different types of tumors:
Epithelial tumors
- Make up 85 to 90% of ovarian/fallopian tube cancers
- Start from the cells that cover the outer surface of the ovary
Germ cell tumors
- Start from the cells that develop into eggs
Stromal tumors
- Start from the structural cells that hold the ovary together and produce hormones called estrogen and progesterone
Risk factors
The cause of ovarian cancer is not yet known, but there are several risk factors that may increase a woman's risk. These risk factors can include:
Middle age or older: Ovarian cancer occurs most often in people after menopause (half of all ovarian diagnoses occur at 63 years of age or older)
Direct family history of ovarian, breast, prostate, or colorectal cancer
Having never experienced childbirth, having children later in life or difficulties in conceiving
Other gynecologic conditions like endometriosis, which is a condition where tissue from the lining of the uterus grows elsewhere in the body
Prior history of breast, uterine or colorectal cancer
Having genetic mutations including BRCA1 or BRCA2 or one associated with Lynch syndrome
Race/ethnicity: certain ethnic groups have a higher risk of developing ovarian cancer
Long-term use of hormone replacement therapy, especially estrogen alone for more than 10 years, may be associated with an increased risk
Please note that the risk factors listed above are not exhaustive.
