Cervical Screening Awareness Week
EVENT - 12TH JUNE 2017
Gynaecologist and gynae oncologist at The McIndoe Centre For Gynaecologic Oncology, on the importance of cervical screening in the run up to Cervical Screening Awareness Week
What is cervical screening?
Cervical screening is about trying to pick up abnormalities in the skin of the cervix which if left, might become cancers. We know we have a marginal window with cancer of the cervix, because there are these precancerous abnormalities which persist—over some years, usually—before the cancer develops. The smear test involves collecting cells which have fallen off the skin of the cervix, putting them on a slide, staining them, and looking at them under a microscope. You can see where the cells are a bit abnormal, and you can grade them by degree of abnormality.
What happens then?
If you get a high grade abnormality—that is, if they are significantly abnormal—you go off for a colposcopy examination (a simple procedure used to look at the cervix), to see whether they are cancerous. If it is borderline—that is, mildly abnormal—then what they tend to do is test for HPV. If you are HPV positive, you will be sent for colposcopy; if negative, well, then you are reassured, because you are very unlikely to get an abnormality if you are HPV negative. Indeed, we are shifting toward making HPV testing the primary test instead of the smear test, because there is such a direct link between cervical abnormality and HPV.
What is HPV?
HPV stands for human papilloma virus. It has no symptoms, really: most of us clear them within a few years naturally, like hand warts, and you only know you have it if you test for it, but we know that women can’t have significant abnormalities of the cervix if they aren’t infected with HPV. A HPV infection doesn’t necessarily mean you have abnormalities, but if you are HPV negative you are very unlikely to have them. The smear test has saved many lives, but according to a big study done in the United States recently, it only picks up about half of the potential abnormalities. False negatives are pretty common and by HPV testing first, we would miss many fewer women. We can triage them, so if they are HPV positive, we can keep a closer eye going forward.
Can you vaccinate against this virus?
Yes, that is one good thing on the horizon. We introduced a national vaccination programme for young women 10 years ago, where girls of 12 or 13 are vaccinated against HPV, and we think it will prevent up to half of cervical cancers developing. We hope that as this cohort of women—the first of whom will be about to go into their mid to late twenties now—pass through the high-risk years of 25 to 30, we see a reduction in incidences of cancer.
Of course, there is a risk that it introduces complacency, so it’s important to emphasise that even if you have been vaccinated, you are still at risk and should do smear tests every three years. One thing we have learnt in the last few years is that women can become re-infected with HPV, because it can be sexually transmitted. Women in their twenties, thirties and forties might want to bear that in mind.
What issues are there with cervical screening?
One of the things I find personally quite shocking is that we have raised the screening age from 20, which is what it used to be 15 years ago, to 25 years of age—yet the peak incidence for cancer of the cervix is between 25 and 30. This means we are effectively offering the women in that age group one smear test, at 25, to try and prevent them all getting cancer. What’s happened as a result is that for women in this age group, the incidence of cancer has gone up by 50 per cent. You need to pick up abnormal cells in the cervix when they are pre-cancerous, not when they are cancerous.
The reasoning behind it is that a statistician called Professor Peter Sasieni looked at young women who had smear tests and saw that some of them went on and had cancer anyway and he developed this theory that the smear test didn’t really work in young women, whereas it seemed to work in older women. Yet the reason it works in older women is that if women have had a smear test every three years between 20 and 30, by the time they get to 30 they have had three or four smears and the chances of picking up an abnormality is higher than if a woman has had one smear at 20, then gets cancer at 23 or 24. It is about exposure.
The only reason the smear campaign has been successful, I would argue, is because women have repeated smears. It is the number that count. You can’t give a whole population of women one smear at 25 and expect them to be protected. It is a major problem, I think, which we have tried to address but to no avail. If you want a smear test at 20, you have to go private now: the NHS will not provide it.
Figures suggest one in four women invited for cervical cancer screening in England last year failed to attend. Why do you think that is?
I think the reason is that it is quite an uncomfortable, intrusive examination and there isn’t widespread awareness of its importance. When Jade Goody died of cancer of the cervix, everyone rushed out to have a smear test, but people soon moved onto other things. It’s difficult to keep that level of interest up. Access to healthcare varies enormously and in this area, more than most—though chaperones are available pretty much universally for intimate examinations nowadays, and if you want a woman to do the test for you, you can specify that, too.
What do you think the answer to that is?
When a celebrity has the illness, it is a good opportunity to highlight it of course, but beyond that I think we need to go over some of the key bits of information. I think the fact that the peak age of incidence is between 25 and 30 would come as a shock to most young women, because most cancers are associated with women of an older age. The prospect of having your womb removed is very different to a woman at 25 than it is one at 50, who may have already had kids.
What are the main symptoms of cervical cancer?
The main symptom is irregular bleeding: after sex, between periods, or any time, really. Sometimes there is a smelly vaginal discharge too, but irregular bleeding is the most common.
And the prognosis?
If you pick it up early enough—and lots are picked up early, sometimes with just a smear test—then the rate of survival is nearly 100 per cent. However, with late stage cancer—incidences of which are fortunately very few—then the rate is down to around 50 per cent. And a late stage disease is a risk if you have had no smears at all.
For more information, visit The McIndoe Centre For Gynaecologic Oncology