Let’s talk about risk factors for a moment. Did you know that a risk factor is anything that raises your chance of getting a disease, like cancer? Different cancers: different risk factors.
When it comes to cervical cancer, by far the most important risk factor is infection by the human papillomavirus or HPV, a group of more than 100 related viruses that can infect cells on the surface of the skin, genitals, anus, mouth and throat. HPV is passed from one person to another during skin-to-skin contact. HPV can be spread during sex -- vaginal and anal -- and even during oral sex.
However, intercourse doesn't have to take place for HPV to spread from one person to another. All that is needed is skin-to-skin contact with an area of the body infected with HPV.
Although scientists believe that it is necessary to have contracted HPV for cervical cancer to develop, most women with this virus do not eventually develop cancer. Doctors widely believe that other factors must come into play for cervical cancer to develop. Here are ten of the most common:
- Smoking: Women who smoke are about twice as likely as non-smokers to get cervical cancer. Tobacco smoke exposes the body to many cancer-causing chemicals that affect organs other than the lungs. These harmful substances are absorbed through the lungs and carried in the bloodstream throughout the body. Tobacco by-products have been found in the cervical mucus of women who smoke. Researchers believe that these substances damage the DNA of cervix cells, contributing to the development of cervical cancer.
- Immunosuppression: Human immunodeficiency virus (HIV), the virus that causes AIDS, damages the body's immune system and causes women to be more likely to become infected with HPV. This may explain the increased risk of cervical cancer in women with AIDS. Scientists also believe that the immune system is important in destroying cancer cells and slowing their growth and spread, so women infected with HIV have a higher-than-normal risk of a cervical pre-cancer developing into invasive cancer, and the cancer may develop at a faster rate than in women without HIV.
- Chlamydia infection: Chlamydia is a relatively common kind of bacteria spread by sexual contact that can infect the reproductive system. Chlamydia infection can cause pelvic inflammation, leading to infertility. Some studies have seen a higher risk of cervical cancer in women whose blood test results show signs of past or current chlamydia infection compared with women with normal test results. Since chlamydia often causes no symptoms in women, a woman may not know that she is infected at all unless she is tested for the infection when she gets her annual pelvic exam.
- Diet: Women with diets low in fruits and vegetables may be at increased risk for cervical cancer. Overweight and obese women are more likely to develop adenocarcinoma (glandular cancer) of the cervix.
- Oral contraceptives (birth control pills): Credible evidence suggests that taking oral contraceptives for a long time increases the risk of cancer of the cervix. Research suggests that the risk of cervical cancer goes up the longer a woman takes oral contraceptives but the risk goes back down again after oral contraceptives are stopped.
In a 2007 study, the risk of cervical cancer was doubled in women who took birth control pills longer than 5 years, but the risk returned to normal 10 years after dosing ended. Experts suggest women discuss with their health care provider if the benefits of birth control pills outweigh potential risk. A woman with multiple sexual partners should use condoms to lower her risk of sexually transmitted infections no matter what other form of contraception she uses.
- Multiple full-term pregnancies: Women who have had three or more full-term pregnancies have an increased risk of developing cervical cancer, but no one really knows why this is true. One theory is that these women had to have had unprotected intercourse to get pregnant, so they may have had more exposure to HPV. Studies have also pointed to hormonal changes during pregnancy as possibly making women more susceptible to HPV infection or cancer growth. Another thought is that the immune system of pregnant women might be weaker, allowing for HPV infection and cancer growth.
- Young age at the first full-term pregnancy: Women who were younger than 17 years-old when they had their first full-term pregnancy are almost twice as likely to get cervical cancer later in life than women who waited to get pregnant until they were 25 years or older.
- Poverty: Believe it or not, living in poverty is a risk factor for cervical cancer. Many women with low incomes do not have ready access to adequate health care services, including Pap tests. This means they may not get screened or treated for cervical cancers and pre-cancers.
- Diethylstilbestrol (DES) is a hormonal drug given to some women to prevent miscarriage between 1940 and 1971. Women whose mothers took DES when pregnant with them are often called “DES daughters.” These women develop clear cell cancer of the vagina or cervix more often than would normally be expected in the population. This type of cancer is extremely rare in women who are not DES daughters. There is roughly one case of this type of cancer in every 1,000 women whose mother took DES during their pregnancy. This means that about 99.9% of DES daughters do not develop these cancers. DES daughters may also be at increased risk of developing squamous cell cancers and pre-cancers of the cervix linked to HPV. Although DES daughters have an increased risk of developing clear cell carcinomas, women don’t have to be exposed to DES for clear cell cancer to develop. While it is extremely rare, women were diagnosed with the disease before DES was invented.
- Family history of cervical cancer: Cervical cancer may run in some families. If a woman’s mother or sister had cervical cancer, her chances of developing the disease are 2 to 3 times higher than if no one in the family had it. Some researchers suspect this familial tendency is caused by an inherited condition that makes some women less able to fight off HPV infection than others.
When thinking about cervical cancer risk factors, focus on those that you can change or avoid –like smoking or human papillomavirus infection— rather than those that you cannot. However, it is still important, to know about risk factors that can't be changed so women who have these factors can get regular Pap tests to detect cervical cancer early. If detected early, cervical cancer is one of the most successfully treatable cancers.
Lynette Summerill, is an award-winning journalist who lives in Scottsdale, Arizona. In addition to writing about cancer-related issues, she writes a blog, Nonsmoking Nation, which follows global tobacco news and events.
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