Risks of Ovarian Cancer

The first step in evaluating a woman’s risk for ovarian cancer is a thorough review of her personal and family health history. Women Knowledge of the risk factors associated with ovarian cancer is essential for nurses to tailor patient care and teaching. Without an accurate and comprehensive risk assessment, selecting appropriate strategies for cancer prevention and early detection is impossible.

Age

As with most cancers, increasing age is the most significant risk factor for the development of ovarian cancer. Women ages 75–79 have the highest incidence of ovarian cancer, with a rate of 60 cases per 100,000 women. The mean age of developing ovarian cancer in the United States is 58 years (National Cancer Institute, 2002). Incessant ovulation over time is one theory that may help to explain why age is a significant risk factor in ovarian cancer development.

Personal History of Cancer

A personal history of breast or colon cancer increases the risk of developing ovarian cancer three to four times more than the general population’s risk. In women diagnosed with breast cancer before age 50, the risk of developing ovarian cancer increases as much as fourfold. The association between breast and ovarian cancer may be a function of shared risk factors and, in select cases, a common genetic basis including an inherited mutation for BRCA1 and BRCA2. Both breast and ovarian  cancer also share an increased incidence among women of higher socioeconomic status, suggesting a role for environmental or lifestyle factors. The precise nature of these risk factors is not understood clearly.

A personal history of colon cancer increases the risk of developing ovarian cancer, especially in women diagnosed with colon cancer before age 50. The association between colon and ovarian cancer appears to be bidirectional (i.e., colon cancer risk increases after ovarian cancer, and ovarian cancer risk increases after colon cancer), although most women who develop ovarian cancer will not survive long enough for the risk of colon cancer to become a factor. The risk of developing multiple primary cancers of the colon and ovary may be related to hormonal and nutritional interactions or their relationship with regard to hereditary nonpolyposis colorectal cancer (HNPCC) syndrome. HNPCC syndrome is an inherited syndrome that may increase a person’s risk of developing colon, endometrial, and ovarian cancers.

Family History of Cancer

A family history of ovarian cancer can significantly increase a woman’s risk of developing ovarian cancer. Joan is worried that her daughters are at higher risk because of her history of ovarian and breast cancer. When a woman has one first-degree relative affected with ovarian cancer, her chance of developing ovarian cancer by age 70 increases from 1.8%–4.7%. Having two which may increase their chances of developing breast and ovarian cancer. Oncology nurses must have an understanding of cancer genetics and be able to incorporate this knowledge into the care of their patients. Middelton, Dimond, Calzone, Davis, and Jenkins (2002) recently published a comprehensive guide to cancer genetics for nurses. Referring women to genetic counselors, gynecologic oncologists, or advanced practice nurses specializing in risk assessment is appropriate when a hereditary mutation is suspected and also when a need exists for more specific cancer prevention and detection recommendations. The interaction between personal and family history of cancer can be complicated and may require expert resources to interpret this complex information for patients. first-degree relatives affected with ovarian cancer increases the risk to 7%–10%.

An inherited genetic mutation is the causative factor in 5%–10% of cases of epithelial ovarian cancer. A BRCA1 mutation may increase a woman’s risk of developing ovarian cancer by age 70 by 20%–44%. A BRCA2 mutation may increase the risk of developing ovarian cancer from 10%–27%. HNPCC syndrome accounts for 2% of all ovarian cancers and may increase a woman’s risk of developing ovarian cancer as much as 12%.

Endocrine factors such as nulliparity and infertility have been cited as contributing to the development of ovarian cancer. The increased risk may be related to uninterrupted ovulation or increased levels of hormones associated with ovulation. Women who never have been pregnant have a slightly higher risk of developing ovarian cancer as compared to women who have had more than one child. Distinguishing between women who choose infertility versus women who have undesired infertility is important. Women who choose infertility have lower rates of developing ovarian cancer. This probably is related to the use of oral contraceptives and, in some cases, tubal ligation. Women who begin menstruating early or start menopause late do not have an increased risk of developing ovarian cancer. Although fertility drugs once were thought to be associated with higher rates of ovarian cancer, recent studies have contradicted the idea. No association has been found between use of fertility drugs and epithelial ovarian cancer, although use of fertility drugs is associated with a slight increase in nonmalignant serous tumors.

Diet and Obesity

Industrialized nations have the highest rates of ovarian cancer, suggesting that certain dietary factors may be associated with an increased risk of developing it. A diet high in fat may increase the risk, and a diet high in fiber may decrease the risk. In two studies, the increased risk and protective effect seen with certain dietary factors were minimal. A recent study examining the relationship between obesity and ovarian cancer found a twofold increase in premenopausal ovarian cancer risk with a body mass index (BMI) of 25 kg/m2 or higher versus women with a BMI less than 20 kg/m2. Researchers have theorized that endogenous levels of hormones, specifically estrogen, may affect the risk of developing ovarian cancer. In another study, an inverse relationship between increasing body weight and the risk for ovarian cancer was found. This effect may be related to an increased number of anovulatory cycles associated with higher BMI. More studies are needed to clarify the relationship between obesity and ovarian cancer risk.

Talc

Perineal talc exposure has been cited as a risk factor in the development of ovarian cancer because of its similarity to asbestos. The theory was refuted with study findings indicating that women who used talc daily for more than 20 years had no increased risk for the development of ovarian cancer.

Hormone Replacement Therapy

The use of hormone replacement therapy (HRT) recently was linked to an increased risk of ovarian cancer. Women who used estrogen-only therapy, especially those who used estrogen replacement for more than 10 years, were at significantly increased risk for developing ovarian cancer. Additional studies evaluating the relationship between HRT and ovarian cancer risk have not been consistent. In one study evaluating various HRT preparations, no significant links were found between ovarian cancer risk and any use of HRT.

Last updated Nov 26/06