Are Fluid-Based Cytologies Superior to the Conventional Papanicolaou Test? A Systematic Review

FBC offers the advantage of doing HPV testing on the same Pap specimen in triaging the patient diagnosed with ASCUS. As shown in the ASCUS/LSIL Triage Study,61 patients with ASCUS Pap test results and negative human papillomavirus studies can be followed with annual Pap tests without colposcopy or more frequent screening.

Limitations

The greatest limitation of the studies was the lack of comparision of Pap test results and colposcopy with biopsy of any suspicious areas. We therefore also included studies that used an alternative reference standard for women with negative Pap results. However, the use of different reference standards for patients with positive and negative test results has been shown to result in overestimates of test sensitivity.⁸ The fact that none of the studies addressed the issue of blinding in interpretation of the reference standard is also of concern. Perhaps the most important limitation involves the fact that the patients included in these studies came from high-risk populations. It is not clear how well these results will generalize to the many women at low risk who receive Pap tests in the offices of American primary care physicians. An additional limitation of our study includes the potential for publication bias, since we included only those articles written in English.

Conclusions

Before widespread adoption of this new FBC technology, it would be advisable to have additional acceptable reference standards studies, designed to avoid verification bias and to ensure that equivalent specimen collection methods are used. Once reliable estimates of the relative sensitivity and specificity of the FBC Pap test are available from such investigations, a decision can be made about whether the benefits derived from widespread adoption would outweigh any disadvantages or additional costs.