Liquid no better than conventional cervical cytology

Liquid-based cervical cytology is no more sensitive or specific than a conventional Pap smear for detecting high-grade cervical intraepithelial neoplasia, according to a recent systematic review and meta-analysis conducted in the Netherlands.

Upon reviewing eight relevant studies and one randomized clinical trial published between 1991 and 2007 that all employed gold standard verification of results, the authors of the meta-analysis concluded that other than a slightly lower specificity for liquid-based cytology when atypical squamous cells of undetermined significance is the cutoff (OR, 0.91; 95% CI, 0.84-0.98), virtually no difference exists between the two methods.

Other factors that could tip the scale one way or the other when choosing which method to use include whether samples for liquid-based cytology are compromised when they are first used for conventional Pap smear, that cytotechnologists and pathologists consistently prefer liquid-based cytology because the uniform spread of epithelial cells in a thin layer facilitates microscopic interpretation, and that the liquid-based technology is more costly.

Arbyn M, Bergeron C, Klinkhamer P, et al. Liquid compared with conventional cervical cytology: a systematic review and meta-analysis. Obstet Gynecol. 2008;111:167-177.