Cervical Cancer

Description

Alternative Names

Risk Factors

An estimated 12,200 American women will be diagnosed with invasive cervical cancer in 2003. The incidence has been declining steadily over the past decades. Fifteen percent of women with cervical cancer develop it before the age of 30. Of concern is an increase in cancer rates in women younger than twenty. (This increase may simply be due to more women being screened and so diagnosed at an early age.) If young women with early abnormal changes do not have regular examinations, they are at high risk for carcinoma in situ by the time they are age 40 and for invasive cancer by age 50.

Socioeconomic and Ethnic Factors

Although the incidence of cervical cancer has declined in both Caucasian and African American women over the past decades, it is much more prevalent in African Americans, and their mortality rates are twice as high as those in Caucasian women. This difference, however, is almost certainly due to social and economic differences. A 2001 study of women in the military found no differences in mortality rates when there is equal access to the same treatments.

Hispanic American women also have more than twice the risk of invasive cervical cancer as Caucasian women due to a lower rate of screening. This lower rate, particularly in immigrants from Mexico, may be due to cultural beliefs that Pap smears might be viewed as an "admission of immorality." Fortunately, evidence in 2002 suggests that screening is increasing in young Hispanic women.

Specific Risk Factors for Human Papillomavirus

The human papillomavirus (HPV) is the primary cause of cervical cancer. Between 12% and 46% of American women carry the virus. The risk for cervical cancer in infected women appears to be highest in those infected with HPV for more than six months. In most people, the virus goes away within a year. In about 10% of infected women, however, the infection persists.

High Sexual Activity. In adults, the most important risk factor for HPV is sexual activity with an infected person. Women most at risk for cervical cancer are those with a history of multiple sexual partners, sexual intercourse at an early age (17 years or younger), or both. A woman who has never been sexually active has a very low risk for developing cervical cancer. Sexual activity with multiple partners increases the likelihood of many infections in addition to human papillomavirus.

Douching. Women who douche on a weekly basis are more likely to contract cervical cancer than those who do not. Douching may destroy the natural antiviral agents normally present in the vagina, making women more susceptible to HPV.

Pessaries. Use of a pessary (a ring-shaped plastic device that keeps the vagina and uterus from collapsing) increases the risk of chronic inflammation and viral infection at the insertion site and therefore may increase the risk for cervical cancer.

Risk Factors for HPV in Children and Infants. HPV also can occur in children and even newborns, however, so the virus may also be transmitted by an infected mother. In children, HPV is usually the harmless form that cause skin warts.

Inherited Genetic Factors

In one analysis, between 15% and 20% of women with cervical cancer had at least one close relative with the disease. Two studies have also reported that in families with cervical cancer there have also been higher rates of other HPV-related and smoking-associated cancers. Inherited factors in such cases most likely cause changes in the immune system that make such people more susceptible to HPV or other viruses.

Use of Oral Contraceptives

A number of studies, including a major analysis, have reported a strong association between cervical cancer and long-term use of oral contraception (OC). The risk is highest (up to four times the risk of nonusers) in women infected HPV who have taken OCs for ten years or more. (Women taking OCs for less than five years have no significantly higher risk.) The reasons for this risk from OC use are not entirely clear. Certainly, women who use OCs are less likely to use a diaphragm, condoms, or other methods that offer some protection against sexual transmitted diseases, including HPV. Some experts also suggested that the hormones in OCs might facilitate entry of the HPV virus in the genetic material of cervical cells

Having Many Children

Studies indicate that having many children increases the risk for developing cervical cancer, particularly in women with HPV.

Smoking

Several studies have associated smoking with a higher risk for precancerous changes (dysplasia) in the cervix and for progression to invasive cervical cancer. It is not clear if this association is due to impairment of immune system or direct cancer-causing effects by cigarette smoke. One study detected carcinogenic substance from tobacco in cervical cells of women who smoke. Cigarette smokers are also deficient in folate, a B vitamin. Such deficiency plays a role in the development of dysplasia.

Exposure to Chemicals

Diethylstilbestrol (DES). Diethylstilbestrol (DES), an estrogen compound, was used by pregnant women in the 1940s and 1950s. The daughters of these women face a higher risk for cervical cancer, genital tract abnormalities, and miscarriage.

Environmental Chemicals. One study has reported an increase in cervical cancer mortality in women whose jobs exposed them to harmful chemicals. Such women worked in manufacturing, personal services, farm work, and as nursing aides. More research is needed.