A pioneering trial can discover the threat of cervical cancer early, but it comes with a few pitfalls
SCIENTISTS have developed a new test for cervical cancer which could reduce the toll of 1500 deaths each year.
Given the fallibility of the current smear tests - which miss up to 40 per cent of abnormalities - it sounds perfect. But the new wonder test comes with its own pitfalls.
The Hybrid Capture test picks up the presence of the most common sexually- transmitted infection in the western world.
The virus is HPV, the human papilloma virus, recently pinpointed as the major cause of the second biggest cancer killer in women world- wide.
It's a wart virus found in more than 99 per cent of cervical tumours. The virus does its damage by invading the DNA of cells in the cervix, where it makes the cells carry on dividing in an unregulated manner. In time, these may mutate into a cancer that carries a 50 per cent mortality rate.
The newly-developed test is the only way to detect HPV infection. And clearly detecting the virus means that cancer could be discovered earlier. Carried out in the same way as a smear, it may eventually replace it.
But the virus is incredibly common - up to three quarters of women are estimated to come into contact with it at some time. And not all of those will go on to develop cancer.
So what happens to the one-fifth of women under 35 who test positive? The virus has no symptoms and, more importantly, no treatment.
In most women, it won't matter - it clears over time as the body mounts an immune response, much the same as a cold or flu. But with no treatment, they must live with the worry it may develop into something more sinister.
Dr Maggie Cruickshank, senior lecturer in gynaecological oncology at Aberdeen University, said: "Until we know who is really at risk, introducing the test would be a complete disservice to women."
While researchers are still testing the effectiveness of the Hybrid Capture on a group of 12,000 women, including some women from Edinburgh, the test is already available in private clinics. You can even send away for a pounds 44 kit and ask your GP to do the test for you.
For a woman who has had one abnormal smear, having the Hybrid Capture test may help to understand why she has abnormal cells.
But there are complications. A woman who has tested positive for a sexually- transmitted infection may have to face questions about the fidelity of her partner, or worry that she may infect him.
Without further testing, it will be impossible to know when the infection has gone.
And she will still have to wait until doctors have carried out three - unreliable - smears before they can have a colposcopy, the microscopic examination of the cervix which gives a definitive yes or no to the threat of cancer.
Dr Anne Szarewski, of the Imperial Cancer Research Fund, is carrying out the current trials. She said: "The national screening programme is waiting before introducing the HPV test because we actually don't know how good the test is in a screening setting.
"As there is a high positivity rate among young women, who don't all go on to get cervical cancer, then I suspect it won't be recommended for screening for women under 30 as this would cause …