More than 90% ovarian cancers are classified as “epithelial” and are believed to arise from the surface (epithelium) of the ovary. However, some evidence suggests that the fallopian tube could also be the source of some ovarian cancers. Since the ovaries and tubes are closely related to each other, it is thought that these fallopian cancer cells can mimic ovarian cancer. Other types may arise from the egg cells (germ cell tumor) or supporting cells. These cancers are grouped into the category of gynecologic cancer.
Causes & Risk Factors
Ovarian cancer is the fifth most common cancer among women, and it causes more deaths than any other type of female reproductive cancer.
The cause is unknown.
The risk for developing ovarian cancer appears to be affected by several factors. The more children a woman has and the earlier in life she gives birth, the lower her risk for ovarian cancer. Certain genes (BRCA1 and BRCA2) are responsible for a small number of ovarian cancer cases. Women with a personal history of breast cancer or a family history of breast or ovarian cancer have an increased risk for ovarian cancer.
Older women are at highest risk.
Risk Factors include:
Genetic mutation: The most significant risk factor for ovarian cancer is having an inherited mutation in one of two breast cancer genes, BRCA1 or BRCA 2. They are responsible for about 5 -10 % of ovarian cancers besides playing a role in endometrial and uterine cancers. Acquired mutations in tumor suppressor gene p53 or HER2 oncogene also induces ovarian cancer.
Family history: Familial factor plays a very important role in estimating the risk of ovarian cancer. A woman has about 50% risk of developing ovarian cancer if two or more first-degree or second-degree relatives have had the disease.
Age: It is an important risk factor and about 50% of all ovarian cancers occur in women older than 65 yrs.
Personal history: Women who have had breast or colon cancer may have a greater chance of developing ovarian cancer.
Fertility drugs: Drugs used for ovarian hyperstimulation increases the risk of developing ovarian cancer.
Diet: Diets that are high in animal fats have been linked to the development of ovarian cancer.
Talcum powder: Some studies suggest that women who use talc in the genital areas are at increased risk of ovarian cancer. Talc sometimes contain asbestos, a known cancer-causing agent.
Ovarian cysts: Ovarian cysts that occur after menopause increases the risk of ovarian cancer.
Hormone replacement therapy (HRT): Replacing hormones, like estrogen, after menopause increases the risk of developing ovarian cancer.
Obesity: Women who are obese by age 18 are at an increased risk of developing ovarian cancer before menopause.