The failure of such a device may be one reason why the false negative rate in pap smears can be as high as 55 per cent in some areas.

Researchers at St Mary’s Hospital, Manchester examined 39 studies of various devices used for collection of cervical cells and compared their ability to identify two well known markers of cancer, endocervical cells and dyskaryosis. Their findings have produced something of a shock for proponents of regular screening.

They also show that the accuracy of a smear test is may depend entirely on which device is used.

The most effective single devices were shown to be those with an extended tip; the Ayre’s spatula has a double rounded tip. The most accurate method of collection was a combination of an extended tip spatula and a small cervical brush.

The choice of device in any practice, say the authors, is usually down to habit, rather than effectiveness, and many doctors do not like using the combination of devices because it is more time consuming.

The authors recommend that, at the very least, extended tip spatulas should replace the Ayre design, and that this recommendation should be incorporated into national screening programme protocols (Lancet, 1999; 354: 1763-70).

Investigators at the Centers for Disease Control (CDC) in Atlanta report that 21 per cent of US women have undergone hysterectomy and, over a period of 3 years, 78 per cent of them had a Pap smear, compared with 82 per cent of women with intact uteri. This translates to more than 10 million women who have received an unnecessary Pap smear at a cost of more than 375 million dollars.

Continued screening is only justified for those who have had supracervical hysterectomies (the cervix is left intact) and those originally diagnosed with cervical neoplasia (either benign or malignant tumours), say the researchers. On that basis, only 7-15 per cent of the women with hysterectomy require regular screening.

In spite of these findings, professional organisations such as the American College of Obstetrics and Gynecology and American Cancer Society, continue to recommend that all women should have regular Pap screening (Obstet Gynecol, 2001; 98: 269-78).

Recent research adds weight to a study in 1985, which first linked smoking to the skin condition.

Hywel Williams, a research fellow at St Thomas’s Hospital in London, estimates that smoking may have triggered up to half the cases of palmoplantar pustular psoriasis characterized by thickened plaques on the palms and soles of the feet, which can become cracked and painful.

He said that smoking and drinking should now be added to the growing list of likely causes, alongside trauma, drugs and emotional stress.

“Any progress in identifying modifiable risk factors for this common and socially disabling disease is to be welcomed and it is more useful than reports of temporary remission with expensive and potentially toxic drugs,” he says (BMJ, 12 February 1994).

No research for smear tests

While the British press has been highlighting the blunders of health authorities in failing to recall women for follow up smear tests, they have missed a more fundamental problem.

Britain’s chief medical officer Dr Ken Calman has admitted the cervical smear programme has been implemented ad hoc since the 1960s with no research evidence, leading to variations at the local level. He said the screening programme for hearing loss in children also needed reviewing.

In the UK, over 25,000 cases have so far been reported of women who have failed to receive a follow up request, usually because of an administrative error. The latest case was in South London.

Very few women aged over 50 years develop cancer if they have a history of regular smear tests with normal results, yet, under current medical guidelines they continue to be screened.

A study team from University College London has reckoned that early withdrawal of women at low risk from the regular screening programme could create savings of 25 per cent.

On the downside, there would be an estimated increase of two cases of cervical cancer per 100,000 women each year, which would otherwise have been detected by early screening (BMJ, 1999; 318: 356-61).

l Cervical smears which show a mild to moderate inclination towards cancer are more likely to revert to normal than progress to cancer.

Despite these new findings, women whose smear readings are classed as mildly dysplastic are usually referred for immediate colposcopy and biopsy.

Researchers from University of Toronto recommend a less invasive approach, and they suggest that women with mild dysplastic readings should be screened again in six months (J Nat Cancer Institute, 1999; 91: 252-8).

Some 20,000 tests done over the last five years under the screening programme at the Inverclyde Royal Hospital in Scotland are to be re examined after evidence that the doctor doing the analysis may have misread the results.

On a preliminary re examination, 40 out of 1000 smears taken since 1987 were found to be “abnormal”, or “inadequate” (and so require a repeat test).

The Scottish debacle is the latest in a series of such incidents.

In 1987, in Liverpool, 45,000 tests were re examined and 911 found to have been wrongly diagnosed.

In 1988, in Manchester, a batch of 3000 tests passed as clear were re analyzed and 60 found to be suspect.

Reporting the Scottish incident, the Daily Telegraph (29 April 1993) quotes a cytopathologist at St Bartholomew’s Hospital in London conceding that the tests are always subjective and that even experienced cyto screeners can make mistakes.

It seems that even the government may be waking up to the dubiousness of the test.

According to Pulse (15 May 1993), it is likely to introduce cost cutting restrictions on its availability.

Around three million smear tests are estimated to be carried out each year at a total cost reckoned to be around £100m to £120m.

Last year, the government commissioned a report from the Cervical Screening Programme National Co-ordinating Network following criticism from the Public Accounts Committee that there was too little information on the cost effectiveness of the screening programme.

“It is clear the government is spending far too much on cervical screening considering the results we get,” network member Dr Peter Sasieni, an epidemiologist and researcher at the Imperial Cancer Research Fund, is quoted as saying.

The virus, human papillomavirus type 16 (HPV16), has been found in up to 70 per cent of cases of cervical cancer, but researchers at the Royal Free Hospital in London say it is wrong to single it out as the cause.

Their findings mean a basic change in monitoring among gynecologists. Instead of looking for the virus, they should carefully monitor the make-up of minor-grade cervical disease to determine if it is likely to develop into a serious condition, researchers recommend.

In a study of 200 women, the research team discovered that there was no difference in the progress of disease in women whether they were HPV16-positive or not. They monitored the women for nearly six years.

!AThe Lancet, 13 August 1994.

According to a multi departmental study at the University of Alabama at Birmingham, women deficient in folic acid were more likely to develop cervical abnormalities if other risk factors – number of sexual partners, use of the Pill, smoking or infection with human papillomavirus infection – were present.

In particular, a low level of folic acid increased a woman’s chances of developing cervical dysplasia ie, cervical abnormalities by five times.

In its report Cervical and Breast Screening in England, the audit office found a wide disparity in interpretations of findings and a lack of benchmarks against which to compare results. The audit showed in some areas of England as many as 18 per cent of smears were classified as abnormal, compared to 3 per cent in other areas. These differences were solely due to differences in interpretation of results, said the report.

Doctors also differed widely in how to treat abnormalities. The report stressed that some cases of mild abnormalities would resolve themselves with no intervention, while some doctors would nevertheless opt for treatment like cervical conization, which can cause permanent infertility.

In Liverpool, all abnormal smears were reported severely abnormal; in three of five districts a large number of types of smears were erroneously classified as abnormal.

In one out of six districts there was no fail safe system to ensure that women with abnormal smears were followed up, as is required.

Researchers in Leeds concluded that 1.6 out of every 1000 women with an initial ‘mildly dyskaryotic smear’ will go on to develop cancer if a ‘conservative repeat smear policy is adopted’, with cervical screening every three years. A policy of immediate referral for colposcopy – where the cervix is examined using a binocular instrument called a colposcope and often accompanied by a biopsy – is also associated with a subsequent cancer rate of 1.6 per 1000.

‘Therefore, repeating the smear is almost as effective as an immediate referral to a colposcopy unit,’ they concluded. ‘Even if a five-yearly cervical screening programme is adopted, 2500 women with a mildly dyskaryotic smear will need to be referred for immediate colposcopy to save one additional cancer.’

In its recommendations, called the NHS Cervical Screening Programme, the National Co-ordinating Network concluded that women with minor cell abnormalities, such as “borderline or mildly dyskarotic smears”, should follow a path of “surveillence”. This entails having a repeat smear six months later, only followed by a colposcopy (a visual examination of the cervix through a special instrument) if the smear continues to show abnormality.

It is recommended that women with moderate or severe abnormality be given immediate colposcopy.

These guidelines represent a complete reversal of those of 1987, which recommended that all women with abnormalities of any type be immediately given colposcopy.

The decision is based in part on two admissions, according to Joseph Jordan, a consultant at the Department of Gynaecology, Birminham and Midland Hospital for Women.

The first is that medicine doesn’t understand whether “women with mild cytological abnormalities develop invasive cancer without progressing through more severe degrees of . . .abnormality.”

The second, according to a BMJ study in 1988 (297:18-21), is that “nearly half of all smears with mild abnormalities revert to normal within two years, with no patient developing invasive cancer on longer term follow up.”