Ching

This page is about the risk factors and causes of cervical cancer. There is information on •

How common cervical cancer is About 2,800 women are diagnosed with cervical cancer in the UK each year. Overall, 2 out of every 100 cancers diagnosed in women are cervical cancers. But it is the second most common cancer in women under 35 years old. Added to this, about 24,000 women have a severely abnormal cervical screening result every year. About 4.4 million women are invited for cervical screening each year in England.

HPV infection There are many different types of human papilloma virus or HPV. HPV is the major cause of the 2 types of cervical cancer - squamous cell cancer and adenocarcinoma. It is sometimes called the wart virus or genital wart virus as some types of HPV cause genital warts. In fact, the types of this virus that cause warts are not the types that cause cervical cancer. But there are other types of HPV that are considered 'high risk' for cancer of the cervix. If you have persistent or frequent infections with any of these 'high risk' types, you are more at risk of developing pre-cancerous cervical cells or cervical cancer. If you have infection with more than one HPV type, you have a higher risk of getting precancerous cells on your cervix than women infected with only one type. Women who get cervical cancer have had past infections with HPV. High risk types of HPV can cause changes in the cells covering the cervix that make them more likely to become cancerous in time. But, on the other hand, most women infected with these viruses do NOT develop cervical cancer. So there must be other factors at work. A vaccine to prevent HPV infection has now been licensed for use within the European Union. This vaccine prevents against the strains of HPV that are most likely to cause cervical cancer. But it is not complete protection against all strains. As it takes between 10 and 20 years for a cervical cancer to develop after HPV infection, it will still be important for women to carry on with cervical cancer screening. It will take some years before the introduction of a vaccine has a major effect on the number of cases of cervical cancer. All girls aged 12 or 13 in the UK are routinely offered the HPV vaccine. A 2 year 'catch up' programme, started in autumn 2008, to vaccinate girls between the ages of 13 and 18. The cervical screening programme will continue as before. HPV is nearly always sexually transmitted. Some researchers say it can be passed on with your hands

or from wet towels, swimming costumes or underwear. Experts working in sexually transmitted disease clinics say this is unlikely because viruses do not usually survive outside the body long enough to infect anyone else. It is the fact that HPV is sexually transmitted that has led to women's sexual behaviour being thought a risk for cervical cancer.

Other sexually transmitted infections A recent study looked at all the research results together and found that having both herpes and HPV infection nearly doubled the risk of squamous cell cervical cancer. This research took account of the number of sex partners women had, as well as their use of the pill. Another study looked at infection with HPV and Chlamydia (pronounced: klah-mid-ee-ah). This found that risk of squamous cell cancer increased by about 70% in women with both infections.

Smoking If you smoke, you are more likely to develop squamous cell cervical cancer. Researchers have actually found cancer causing chemicals (benzyrene) from cigarette smoke in cervical mucus of women who smoke. They think that these chemicals damage the cervix. There are cells in the lining of the cervix called Langerhans cells that specifically help fight against disease. These cells do not work so well in smokers. If you have a 'high risk' HPV infection and smoke, you are twice as likely to have precancerous cells in your screen, or to get cervical cancer. The Langerhans cells are less able to fight off the virus and protect the cervical cells from the genetic changes that can lead to cancer. Remember - if you smoke you are more likely to get cervical cancer. If you have mild pre-cancerous changes in your cervical screen, the cells are more likely to go back to normal without any treatment if you stop smoking.

Poor diet Like smoking, it is unlikely that diet plays any direct part in causing cervical cancer. But if you have a poor diet and are infected with 'high risk' HPV, your body may be less able to fight off the virus. So more cells may undergo the genetic changes that can lead to pre-cancerous cells and then to cervical cancer.

A weakened immune system If you have a weakened immune system, then your risk of many cancers, including cervical cancer is greater than average. If they have HPV infection as well, people with HIV and AIDS, or people taking drugs to suppress their immune systems after an organ transplant, are more at risk of developing cervical cancer.

This is because a healthy immune system normally protects you from cells that have become abnormal. Your immune system will kill them off and so prevent them from becoming cancerous.

The pill Recent research that looked at a number of studies together shows that taking the pill could be a risk factor for cervical cancer. It is not clear why this is. The researchers took account of other factors such as number of partners, smoking and most importantly, infection with HPV. Researchers suspected that there was a link, but clear evidence has not come out of the studies until now. We did think that the pill was statistically linked to cervical cancer because women on the pill are more likely to be sexually active and so more at risk of picking up HPV. Also, they do not necessarily use barrier contraception (condom or cap) which could prevent them picking up the human papilloma (wart) virus. But now it seems that it may actually affect risk directly. About 8 in 100,000 women get cervical cancer every year in the UK. The recent research suggests that amongst women who have taken the pill for at least 5 years, that risk is doubled. But this is still a small risk, and taking the pill can help to protect you against womb and ovarian cancers. The evidence suggests that the risk begins to drop as soon as you stop taking the pill, until after 10 years the risk is the same as if you had never taken it. The important thing to remember is that regular screening can pick up changes in the cervix before a full blown cancer develops. Obviously, this is now even more important for women on the pill.

Circumcision There is some research suggesting that women who have partners who have been circumcised are less likely to get cervical cancer. This may be because men who are circumcised are less likely to get HPV infection. This research took into account different factors relating to sexual behaviour.

Women's hygiene Some research has pulled together a number of different studies on adenocarcinoma of the cervix in women with HPV. This found that risk of cancer was almost half in women who had a bath or shower 6 or more times a week, when compared to women who bathed or showered 1 to 5 times a week. . Results of another study show that cervical cancer risk is probably higher in women with poorer hygiene because they are more likely to get a lasting HPV infection if they are exposed to the virus.

Your sex life You will quite often hear that women who have a lot of different sex partners or women who started having sex young are more likely to get cervical cancer. But really, this is only true because the more men you have sex with and the earlier you start having sex, the more likely you are to pick up an infection with a high risk (cancer causing) human papilloma virus (HPV). And so then you are more at

risk of developing cervical cancer. It is not correct to say that women who get cervical cancer have it because they were promiscuous (slept around). After all, you could have only slept with one man and still caught the virus if he had it. If he's had lots of partners, that will increase your risk because it indirectly exposes you to possible sexual infections from lots of other people. A Cochrane review, published in 1999, found that health education can help women reduce their risk of cervical cancer. Teaching women • • • •

How to use a condom To avoid sex when they are young To reduce their number of sexual partners How to negotiate safe sex

helped them adopt healthy behaviour that lowered their cervical cancer risk. It helped them to protect themselves from unsafe sex and talk to their partners about their need to do this. You can read this review of promoting healthy sexual behaviour in the Cochrane Library. It was written for researchers and specialists so is not in plain English.

Pregnancy There is no evidence at all to say that pregnancy causes cervical cancer. Abnormalities in the cervix may become more visible during pregnancy and so be more likely to be diagnosed. Some women may have a screening test when they are pregnant. Women who are not up to date with their cervical screening are more likely to be offered a test when they go to the doctor because of their pregnancy. This screening might lead to women being diagnosed with pre-cancerous changes or cervical cancer while they are pregnant. But this does not mean that the pregnancy caused the cancer - just that this is when it was picked up.

How many children you have, and when Women in developing countries have higher cervical cancer risk. This is partly because developed countries have screening. It is also because women in developing countries are more likely to have large families. Women who have had 7 or more children have double the risk of women with only 1 or 2 children. Having your first baby early, before 17, also doubles risk, compared to having your first baby at 25 or more. This research also took account of HPV infection, so that doesn’t explain the findings. Other similar research looked at the different types of cervical cancer. They also found a doubling of risk of squamous cell cervical cancer with 3 or more children, compared to no children. But they found that adenocarcinoma risk went up by half (50%). Genetics - race and family links One study has shown that black women with HPV may have a lower cervical cancer risk than white women with HPV. But we need more studies to confirm any effect of race. Another study showed that sisters of women with cervical cancer may have a small increase in risk. But we don’t know whether this is linked to faulty genes, or whether it is due to common lifestyle factors.