Liquid-Based Cytology Not Superior to Pap Test

For the liquid-based cytology (use of cells), the cervical cells are collected with a traditional sampling device and rinsed into a vial with preservation solution rather than being smeared on a slide.

A randomized controlled trial performed in the Netherlands involved 89,784 women ages 30 to 60 years who participated in a cervical screening program at 246 family practices. One hundred twenty-two practices were assigned to use liquid-based cytology and screened 49,222 patients and 124 practices were assigned to use the conventional Pap test and screened 40,562 patients. Patients were screened for cervical intraepithelial neoplasia (CIN) and were followed up for 18 months, through January 2008.

Albertus G. Siebers, M.Sc. of Radboud University Nijmegen Medical Center (Nijmegen, The Netherlandsl), and colleagues compared the screening performance of Pap tests and liquid-based cytology in terms of test positivity rates, histologic detection rates, and positive predictive values (PPVs). They found that liquid-based cytology did not perform better than conventional Pap tests in terms of relative sensitivity and PPV for detection of cervical cancer precursors.

The study was reported in the October 28 issue of Journal of the American medical Association (JAMA). The authors wrote, "Both the intention-to-treat and per protocol analyses demonstrated that liquid-based cytology was not superior to Pap test regarding detection rates of histologically confirmed outcomes. The same was found for the PPVs. Altogether, these findings provide strong evidence that the performance of liquid-based cytology is not superior to that of the conventional Pap test when applied within a well-organized and quality-controlled cervical screening program."

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Radboud University Nijmegen Medical Center