Causes of Ovarian Cancer

Family history. A clear family history of breast or ovarian cancer increases the risk. 

Genetics. Between 10%-15% of ovarian cancers are caused by a mutation in a known gene that has been passed down within a family, such as the BRCA1 or BRCA2 gene mutation. While a woman normally has a 1%-2% risk of developing cancer, a woman with a BRCA1 or BRCA2 mutation has a risk of about 40% and 10-20%, respectively. There are many other known mutations, although these are rare, such as Lynch syndrome, among others. 

Age. 50% of women with ovarian cancer are aged over 60. Even so, some specific rare types affect younger people, including girls, such as germ cell tumours.

Obesity. Obese women are more at risk. 

Endometriosis. Whether endometriosis is a risk factor is still being studied. It may increase the risk of clear cell epithelial and endometrioid cancers. 

Ethnic origin. Women from North America, Northern Europe and those with Ashkenazi Jewish heritage have a higher risk. 

Reproductive history. Women who have not had children, who are infertile (unable to have children) for no apparent reason, or who have not taken birth control pills may have an increased risk. Fertility drugs have also been associated with an increased risk of contracting ovarian cancer, but this has not been shown to be the case. 

Hormone replacement therapy. Oestrogen-only hormone replacement therapy after menopause increases the risk of cancer over time. The risk decreases progressively after the treatment ends. 

Taking birth control pills. These may reduce the risk of developing ovarian cancer by 30-50%. In addition, this reduced risk can last for up to 30 years after you stop taking them. 

Breastfeeding. The protection increases with the cumulative time spent breastfeeding. 

Pregnancy. The more full-term pregnancies a woman has had, the lower her risk. 

Surgical procedures. Women who have had a hysterectomy (partial or total removal of the uterus), a tubal ligation, or a salpingectomy (removal of the fallopian tubes) have a lower risk. Early preventive bilateral salpingo-oophorectomy (removal of fallopian tubes and ovaries) is recommended for women who have been mothers and who are at very high risk of ovarian cancer (BRCA mutations or Lynch syndrome). It is also recommended for patients over 60 years of age who are undergoing pelvic surgery. Salpingectomy may be recommended in young patients who do not wish to become mothers, while undergoing pelvic surgery (hysterectomy, ovarian cystectomy, appendectomy, etc.). Women considering preventive ovarian surgery should discuss the consequences of ovary removal (which involves the cessation of hormonal function, in other words menopause) with their medical team, including the expected preventive benefits.