Test Your Knowledge

The exact cause of ovarian cancer is unknown. Researchers have identified certain risk factors that may increase a patient’s chances of developing epithelial ovarian cancer, which accounts for about 85 to 90 percent of all ovarian cancers, according to the American Cancer Society (ACS). These risk factors do not pertain to other, less common ovarian cancers, such as germ cell tumors and stromal tumors.

It is important to note that only a small number of patients with risk factors for epithelial ovarian cancer will develop the disease. Risk factors for epithelial ovarian cancer include:

• Age. Most ovarian cancers develop after menopause, with two-thirds of all ovarian cancers affecting women over age 55.
  
  
• Reproductive history. There is a higher risk for women who:
  
  
• • Begin menstruation before age 12
  • Have no children
  • Give birth to their first child after age 30
  • Enter menopause after age 50
    

The risk factors listed above and certain studies indicate a relationship between ovarian cancer risk and the number of menstrual cycles a woman experiences in her lifetime. The greater number of total cycles, the higher the risk of ovarian cancer. Hence, a female who begins menstruating at an early age and enters menopause at an older age is at the greatest risk. Pregnancy interrupts menstrual cycles, so women who have never been pregnant and thus have never had their cycle interrupted are also at greater risk.

• Fertility drugs. Some studies indicate that extended use of the fertility drug clomiphene citrate may increase a woman’s risk of developing ovarian tumors, especially if she does not become pregnant while taking the medication. Patients taking fertility drugs should discuss any potential risks with their physician. Because infertility itself also increases the risk of ovarian cancer, further studies are needed to clarify these relationships.

• Family history of certain cancers. Women whose mothers, sisters or daughters have had ovarian cancer have an increased risk of developing the disease. According to the ACS, about 10 percent of ovarian cancers are inherited. Women with a personal or family history of breast cancer caused by an inherited mutation of the BRCA1 or BRCA2 gene also have a high risk of developing cancer of the ovaries – about 45 percent for BRCA1 and 25 percent for BRCA2. These genetic mutations are responsible for 9 percent of ovarian cancers.
  
  The lifetime risk of ovarian cancer for women with mutations of the BRCA1 or BRCA2 gene is estimated to be between 40 and 50 percent by age 70. However, recent research has indicated that women with a family history of breast cancer who do not have the BRCA genes are not at an increased risk for ovarian cancer. In addition, ovarian cancer can increase a patient’s risk of developing breast cancer. Ovarian cancer also affects larger numbers of women with a family history of colorectal cancer.
  
  
• Obesity. Recent studies have indicated an increased risk of ovarian cancer developing among women who are obese or have a sedentary lifestyle. Research also indicates that obese women with ovarian cancer have a poorer chance of survival.

Some studies suggest that hormone replacement therapy (HRT) and the application of talcum powder to the genital area may increase a woman’s risk of ovarian cancer. However, further research is necessary to confirm these findings.

Researchers are also investigating whether tests to identify certain genetic mutations, such as the HER2 oncogene or the p53 tumor suppressor gene, may help predict a woman’s prognosis for ovarian cancer. The effectiveness of these tests remains uncertain, and some specialists believe that further research is warranted.