Common smear test `ineffective'

A FLAW in the cervical screening programme has been uncovered by research showing that one of the most widely used devices for collecting smears is the least effective in gathering the cells that need to be inspected for signs of cancer.

Researchers have found that the traditional Ayre's spatula, which has a broad tip, was much less effective at collecting cells from the part of the cervix where cancer is likely to start than spatulas with more modern designs. Collecting an adequate smear is the most important factor in screening for cervical cancer.

Studies show that up to 55 per cent of the smears collected by some GPs and practice nurses may be inadequate. An adequate smear is one that clearly displays cells collected from the area inside the rim of the cervix, which is the most prone to cancer.

The Ayre's spatula is the simplest and cheapest of those on the market but its continued use will be called into question by the latest finding, based on a review of 34 random controlled trials, published in The Lancet. Dr Pierre Martin-Hirsch and colleagues, from St Mary's Hospital, Manchester, say that as well as being the least efficient at collecting cells from inside the cervix, the Ayre's spatula was also least likely to allow dyskaryosis, the first sign of an irregularity in cells, to be detected.

Problems with inadequate smears have led to recalls involving hundreds of women in the past. One GP was found to be using an ordinary wooden tongue depressor - like a broad lollipop stick.

If the smear does not include the right kind of cells taken from the full circumference of the cervix, or if it is contaminated with blood, it cannot be determined whether it is normal or abnormal and the woman has to be recalled. As well as causing anxiety, recalls are expensive for the NHS. The report says: "The replacement of the Ayre's spatula with extended tip spatulas should be mandatory for mass screening since this is an inexpensive way to improve sampling."

The Ayre's spatula was increasingly being replaced, said the National Cervical Screening Programme.

The researchers also found that in smears collected with the spatula, it was not possible to detect glandular abnormalities that could indicate the rarer but rapidly growing type of cervical cancer called adenocarcinoma, which accounts for one in five cases of cervical cancer.

Last week three women who developed it won a Court of Appeal ruling that the laboratory run by the Kent and Canterbury NHS trust should have detected it in their smears.