Effective alternative to conventional smear test

Media release
10 July 2007

Studies highlight an effective alternative to conventional smear test

But many New Zealand women unaware it is available

Two studies have highlighted the significant benefits of a relatively new cervical screening method, the ThinPrep Pap Test, compared to the conventional Pap smear, but it appears many New Zealand women are unaware it exists.

A landmark Australian study involving 55,000 women, which was published this week in the British Medical Journal, shows the computer assisted ThinPrep Imaging System[1] is 17 per cent more effective in detecting high-grade pre-cancer than the conventional Pap smear.

The leading researchers from the independent study, which was headed up by Dr Annabelle Farnsworth of Douglass Hanly Moir Pathology (Australian laboratory) and the University of Sydney, say the results are extremely important because by detecting lesions at this stage they can be treated before they become invasive cancer.

Dr Farnsworth says the results of the study show we can do even better in the fight against this highly preventable cancer.

“The conventional Pap smear has been the mainstay of screening for more than 50 years.

“Although the new vaccine is a major scientific breakthrough it only offers partial protection against the development of cervical disease. Women will continue to need cervical screening as it is still the only test which detects if a woman with a Human Papillomavirus (HPV) infection has developed clinically significant cell changes.

“The sample used for the ThinPrep System can also be used for HPV and other testing as well, which is another benefit of this method. This new technology provides the perfect test to fit in with the future needs of the cervical screening program,” Dr Farnsworth said.

While there is currently no laboratory in New Zealand with the ThinPrep Imaging System, New Zealand women can still access some of the benefits of the ThinPrep System, as seven out of the eight laboratories who screen Pap Smears are manually processing the ThinPrep Pap Test.

The improved clinical performance of the ThinPrep System was also reported in a study published in February of this year in the journal Diagnostic Cytopathology. The study, conducted by Dr Jennifer Roberts of Symbion Laverty Pathology, in Australia, involving over 11,000 women, compared the performance of the ThinPrep Imaging System with manually read ThinPrep Pap Test slides and manually read conventional Pap test slides.

The findings were that manually read ThinPrep Pap Test slides showed a significant reduction in false negative rates over the conventional Pap test. (A false negative is when abnormal cell changes are missed and the result is reported as normal.) The results were 25.7% false negatives for the conventional pap test and only 2.75% false negatives for the manually read ThinPrep Pap Test which equates to an 89% reduction in the rate of false negatives with the ThinPrep Pap Test.

This is backed up by the information on the NZ Ministry of Health website which states that currently in approximately 20% of cases abnormal cell changes can be missed with the conventional Pap smear test.

New Zealand Gynaecological Oncologist Dr Ai Ling Tan says the reduction of false negatives with the liquid-based cytology is significant for both New Zealand women and clinicians.

“The results are very important as clinicians can be reassured that they can trust the results they get back. ThinPrep is one of the tools in the armoury that clinicians can use to help combat this disease,” Dr Tan says.

Biocare medical liaison Jane McLean says anecdotal feedback and her own experience at health expositions indicates that there are a significant number of women who are totally unaware of the existence of an alternative to the conventional Pap smear.

Liquid-based cytology is already the standard of care in the UK and Ireland, and the ThinPrep Pap Test is extensively used throughout the western world. In the United States approximately 70 per cent of all Pap tests screened annually are ThinPrep Pap Tests, making it the de facto standard of care.

Women can ask their doctor or healthcare provider for the ThinPrep Pap Test for a small additional fee.

ENDS

[1] The ThinPrep Imaging System, which is an interactive computer system, assists in the primary screening and diagnosis of ThinPrep Pap test slides. The system which was FDA approved in 2003 has been available in Australia since 2004.

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