Our answers to questions asked about HPV infection

Research examining the effects of long-term use of oral contraceptives (the'pill') on the occurrence of cervical cancer in women with human papilloma virus (HPV) has been published in The Lancet.
[Moreno V, Bosch FX, Muñoz N et al. Effect of oral contraceptives on risk of cervical cancer in women with human papilloma virus infection: the IARC multicentric case control study. The Lancet 2002,359:1085 - 1092]

What is HPV?

HPV (human papilloma virus) is a sexually transmitted infection. There are more than 80 human papilloma viruses, a few of which are associated with an increased risk of developing cervical cancer. Exactly how these few high-risk strains of HPV might cause cervical cancer is unknown.

Many women are infected with HPV at some point in their lives, but it is not yet possible to tell who will go on to develop abnormalities of the cervix. Many women will get rid of the virus naturally by the normal functioning of their immune system.

Most HPV infections disappear without causing any problems and even those women who contract high risk HPV rarely go on to develop cervical cancer.

More about HPV

What does the IARC study show?

It shows that women with HPV infection who have been using the pill for over five years are more likely to develop cervical cancer than those who have not. It was, however, carried out in women who live in countries that have no national cervical screening programme in place. In the UK the effectiveness of the NHS Cervical Screening Programme means that cervical abnormalities are usually detected at a pre-cancerous stage, so that cervical cancer is now a relatively rare condition. What the study does demonstrate is the importance of regular cervical screening for all women over 25, whether or not they use the pill.

Is the association between the pill and an increased risk of cervical cancer new?

No, this association is not new. For many years the long-term use of the pill has been linked with an increase in cervical cancer. This has been included in prescribing information and the leaflets in pill packets for a long time. What has been unclear in the past is how much of the association is due to the pill and how much to other factors such as sexual behaviour and smoking. While the IARC study increases the evidence that the pill plays a role in the development of cervical cancer it does not completely prove it. The pill is highly effective at preventing pregnancy and is generally very safe - its benefits far outweigh its risks for the vast majority of women who take it.

Should I be worried by these results?

Women who have regular cervical screening significantly reduce their chances of developing cervical cancer. Cervical screening is not 100% perfect but regular attendance reduces a woman's chance of developing cervical cancer by between 80 and 90%.

If you are between 25 and 64, and you are, or have been, sexually active and not had cervical screening in the last five years,then you should have one as soon as possible. You should make an appointment with your GP, family planning clinic or GUM (genito-urinary medicine) clinic, if you attend one. This is particularly important if you also use the pill.

What does the new research show about my risk of getting cancer?

Because the NHS Cervical Screening Programme is so effective, your overall risk of getting cervical cancer is very low. In 1990, there were about 15 cancers per 100,000 women per year and this fell to about nine per 100,000 by 1996. There are now about four deaths per 100,000 women per year. In the IARC study, women who used the pill for less than five years had the same risk as those who had never taken it. In those who took the pill for five to nine years, the risk was nearly three times higher than for women who had never used it, whereas in those who had used it for more than 10 years, the risk was four times higher. However, whether or not you take the pill your overall risk is still extremely small. The benefits of oral contraception far outweigh the potential risks for the vast majority of women.

What should I do if I've been using the pill for more than five years?

While your risk of developing cervical cancer may be slightly higher if you have been using the pill for more than five years there is absolutely no benefit in stopping taking the pill immediately. Cervical cancer takes many years to develop and in any event is very rare. The NHS Cervical Screening Programme prevents between 80 and 90% of cancer cases in women who attend for regular cervical screening by detecting and treating early abnormalities.

However, if you feel that you do want to stop using the pill in the longer term, you should make a routine appointment to discuss alternative forms of contraception with your doctor or family planning adviser. In the meantime you should continue to take your pill, as you can become pregnant at any time after stopping.

I used to use the pill - what is my risk of cervical cancer?

The study reported in The Lancet found some evidence that risk remained high at least five years after stopping the pill, but there is a lot of uncertainty in this. We do not know whether women who have used the pill in the past are at greater risk of developing cervical cancer than women who have never used it. However, the risk of cervical cancer is very low in all UK women, whether or not they take, or used to take, the pill.

Will women who are long-term users of the pill be screened more frequently by the NHS Cervical Screening Programme?

No. While long-term use of the pill may slightly increase the risk of eventually developing cervical cancer, there is no clear evidence such use increases the speed at which the cancer could develop. Therefore, the current interval of three or five years between tests will remain. Usually, cervical cancer develops very slowly and the purpose of cervical screening is to detect and treat abnormalities which if left untreated might develop into cervical cancer.

I've already been treated for an abnormal result. Does using the pill increase my risk of abnormalities reoccurring?

The study did not have any data on this, and we do not know the answer.

My general practice doesn't do cervical screening. What should I do?

If your general practice does not provide cervical screening, you can visit a family planning clinic or a GUM (genito-urinary medicine) clinic.

I only get an invitation for screening every five years. Is it my right to be screened every three years?

The recommended screening interval is between three or five years depending on your age. Your GP does not have to provide you with cervical screening every three years. However, if you have any unusual symptoms such as bleeding after intercourse or between periods please report them to your GP immediately.

I'm 19 and have been on the pill since I was 15. Should I be screened even though I'm not 25 years old?

We recommend waiting until you are 25 years old as incidence of cervical cancer in young women is rare, and extremely rare in teenagers.

Why don't you screen younger women when they could have been on the pill for several years?

We don't screen teenagers as their bodies, particularly the cervix, are still developing. Because of this a teenager may get an abnormal result when there is nothing wrong. This could lead to unnecessary treatment and we therefore think that screening teenagers can do more harm than good. Cervical cancer is a very slow growing disease, and is very rare in women under 20 - there were only two cases in England and Wales in 1998.

Under the age of 25 years, invasive cancer is extremely rare, but changes in the cervix are common. Although lesions treated in very young women may prevent cancers from developing many years later, the evidence¹ suggests that screening could begin at age 25. Lesions that are destined to progress will still be screen-detectable and those that would regress will no longer be a source of anxiety.

¹(P Sasieni, J Adams and J Cuzick, Benefits of cervical screening at different ages: evidence from the UK audit of screening histories, British Journal of Cancer, July 2003)

What about women over 64?

Women over 64 are invited if their previous two tests were not clear or if they have never been screened.

Women in this age group who have had three consecutive negative tests within the last ten years are known to have a very low risk of developing cervical cancer Screening such women potentially induces more harm than benefit in terms of unnecessary anxiety. There is also an increased likelihood of inadequate samples which occur more frequently in older women.

I've heard that fewer women in London are coming forward for cervical screening than used to. What is the programme doing about this?

In fact, this is true across the country. There is a small but worrying drop in women accepting their invitation for screening. Through its website and other media, the NHS Cervical Screening Programme reinforces the message that cervical screening saves approximately 1,300 lives per year. In 2001 the programme launched the Informed Choice initiative to give women clear, honest and balanced information about the benefits and limitations of cervical screening. Armed with this knowledge, women are able to make up their own minds about whether or not to attend.

Do other European countries have cervical screening programmes?

The UK was the first country in the European Union, and one of the first in the world, to launch a national cervical screening programme based on call and recall. Screening is only organised nationwide in the Netherlands, Denmark, Sweden and Finland. No other national screening programme screens more women than the UK, and we also have the highest coverage.

France has no organised national screening programme, and tests women aged 25 to 65 when they attend their doctor for other reasons. Spain has no organised national screening programme, but has some large regionally organised ones. Germany screens women every year from aged 20, but there is no information on the effectiveness of the programme. Belgium has organised screening only in Flanders, where women are screened every three years from 25 to 64. The Republic of Ireland is currently introducing a screening programme.