(Ivanhoe Newswire) -- Liquid-based cytology, a commonly used alternative to the conventional Pap test, is no better than the Pap test for detecting cervical cancer precursors or cancer.

The Pap test has been considered suboptimal because of a propensity for false-negative and false-positive results. In liquid-based cytology, 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.

Albertus G. Siebers, M.Sc., of Radboud University Nijmegen Medical Centre in Nijmegen, the Netherlands, and colleagues compared the screening performance of Pap tests and liquid-based cytology. The trial involved 89,784 women aged 30 to 60 years who participated in a Dutch cervical screening program at 246 family practices. Half the practices were assigned to use liquid-based cytology and screened 49,222 patients; the other half used the conventional Pap smear test and screened 40,562 patients. Patients were screened for cervical cancer -- cervical intraepithelial neoplasia (CIN) -- and were followed up for 18 months through January 2008.

"Because of randomization, it can plausibly be assumed that the prevalence of CIN was equal in both study groups," study authors wrote. "Therefore, the lack of difference in detection rates and positive predictive value ratios (PPV) in this trial demonstrates that liquid-based cytology is neither more sensitive nor more specific in detecting cervical cancer precursors than the conventional Pap smear."

SOURCE: JAMA, October 28, 2009