Main Cause: HPV Infection
Cervical Cancer Causes
|What Causes Cervical Cancer?
The exact cause of any cancer is still unknown (see cancer causes), probably because so many possible factors are in play. Cervical cancer is no different. Scientists do not know why cells of the cervix become cancerous but there are certain risk factors seem to increase the likelihood of the disease developing. These are:
Human Papilloma Virus (HPV) Infection
Human papilloma virus (HPV) is an STD which is THE major cause of cervical cancer. How it causes cancer is not clear, but the infection seems to cause cell abnormalities. If untreated these abnormalities can develop into cancer. It is now accepted that HPV is responsible for nearly 95 percent of cervical cancer cases. There are more than 150 different versions of the HPV infection of which 40 are transmitted sexually. Some viruses can affect the genital area of both men and women while others can affect the mouth and throat. Most people with the infection will never know they have it. One study estimated that 33 percent of female college students in America have the virus. Fortunately in many cases the body's immune system naturally clears the virus within 2 years of infection. Some types of HPV can cause genital warts in both men and women, and occasionally they can cause warts on the throat. Other types are linked directly to cervical cancer as well as (less commonly) cancer of the vagina, anus, head and neck. HPV is passed through genital contact, most commonly with vaginal or anal intercourse. It can also be passed during oral sex or with direct contact of skin to skin with affected areas. There is no test currently on the market which just screens for HPV, the only test available is used for screening for cervical cancer. If a Pap test comes back with abnormal results, the doctor may then test for HPV to see if it is the cause of abnormal cell changes. As there is no cure for HPV, there is no point in routinely screening for it among the general population. Vaccines to prevent HPV are now common in most schools across Europe, and are also routinely offered to girls between the ages of 12 and 13 in the United States.
Other Sexually Transmitted Diseases
Research also shows a link between other STDs and cervical cancer, namely herpes and chlamydia. Women with herpes and HPV have double the risk of developing cervical cancer, in particular the type known as squamous cell cervical cancer. Another study found that women with both HPV and chlamydia had an 80 percent increased risk of cervical cancer.
Women who smoke or inhale second hand smoke have increased risks of cervical cancer and its pre-cancer form cervical intraepithelial neoplasia (CIN). Toxic chemicals formed from cigarette smoke have been found in cervical fluid and cervical cells. Younger women are even more likely to develop CIN and cervical cancer if they inhale smoke. This is because puberty causes the cervix cells to go through major changes which make them more vulnerable to toxic chemicals. The risk seems to increase if the young woman is also exposed to HPV through sexual contact with an infected partner.
Oral contraceptives, or the pill, may increase the risk of a cervical cancer diagnosis, particularly in women who use them for more than 5 years. The reason for this is not clear; it could be because women on the pill were more likely to be sexually active and so at increased risk of catching HPV. Also, they are less likely to use a barrier contraceptive such as a condom or cap which could prevent infection. Research suggests that the pill could double the risk of cervical cancer. Yet this is a small risk compared to unwanted pregnancies. Also the pill can help protect against womb and ovarian cancer. Studies seem to suggest that risks begin to normalize again when the pill is stopped although this can take up to 10 years.
Many women have heard that having sex younger or having lots of different sexual partners can increase the chances of cervical cancer. This appears to be true in so far as this behavior increases a woman’s chances of being exposed to HPV. One review published in 1999 found that health education can lower a woman's risk of cervical cancer. Teaching young women how to use a condom, how to avoid having sexual relations when they still young and how to reduce the number of sexual partners had positive benefits.
Research shows that women who have had 3 or more full term pregnancies are more likely to develop cervical cancer. The reasons are not clear but one suggested theory is that they have had more chances of exposure to HPV through unprotected sexual intercourse. Another theory is that abnormalities of the cervix are more likely to become visible during pregnancy and so are more likely to be diagnosed. Also, women who are pregnant are more likely to be offered a Pap test which can pick up changes. In other words, the pregnancy does not cause the cancer, merely makes diagnosis more likely. When a woman has her first child also appears to be a factor. Having a first baby before 17 doubles the chances of cervical cancer compared to waiting until the age of 25.
As both CIN and cervical cancer occurs less often in Jewish women scientists began to wonder if male circumcision had a protective effect. Actually there have been suggestions since 1855 that circumcision can protect against many STDS. Most scientists rejected the theory but a new study published in 2002 in the New England Journal of Medicine seemed to lend credibility to the theory. The study showed a clear link between circumcision and reduced risk of HPV and cervical cancer.
A weakened immune system raises the risks of all cancers, including cervical cancer. People with the HIV virus which causes AIDS or those taking drugs to suppress the immune system after an organ transplant are more at risk. This is because a healthy immune system kills off suspicious cells and prevents them from becoming cancerous.
An unhealthy diet increases the risks of all cancers, including cervical cancer. Women who do not include enough fruit and vegetables in their diet may be at increased risk, as well as those who are overweight and obese.
Other Potential Risk Factors
Cervical cancer prevention is possible. The best way to prevent cancer from developing is to have a regular Pap test. A Pap test screens the cells of the cervix to find pre-cancer cells before they turn cancerous. The best way to avoid pre-cancer cells forming in the first place is to avoid exposure to HPV. Avoid have sexual relations too early, with too many partners or with a partner who has had many partners themselves. Wearing a condom (including female condom) can help reduce the chances of catching HPV, but it does not offer complete protection.
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