(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
