1. Home>
2. Specialties>
3. Women's Health>
4. Summary and Comment

Is Liquid-Based Cytology Better Than Conventional Cytology for Cervical Cancer Screening?

Liquid-based cytology detected CIN grade 1, but not CIN grade 2 or higher, more often than conventional cytology.

Liquid-based cytology is widely used for cervical cancer screening, but no large, randomized studies have assessed its accuracy. Italian investigators randomized more than 45,000 women (age range, 25–60) to undergo cervical cancer screening with either conventional or liquid-based cytology. The endpoint was long-term rates of histologically confirmed cervical intraepithelial neoplasia (CIN) grade 2 or higher.

Compared with conventional cytology, liquid-based cytology had a higher sensitivity for detecting CIN grade 1, but not CIN grade 2 or higher, when both atypical cells of undetermined significance and low-grade intraepithelial lesions were used as cutoff points for colposcopy. In fact, liquid-based cytology had a significantly lower positive predictive value for all CIN endpoints. However, liquid-based cytology did significantly reduce the number of results considered unsatisfactory because of obscuring inflammation.

Comment: This study raises a good question. Are we doing Pap smears to detect any abnormal finding, or only high-risk findings? Although liquid-based cytology predicted more mild abnormalities, its sensitivity for detecting high-grade CIN was similar to that of conventional cytology. These findings suggest that the advantage of liquid-based cytology is its lower rate of unsatisfactory slides. What’s more, liquid-based cytology allows reflex testing for human papillomavirus, providing important additional information.

— Wendy S. Biggs, MD

Published in Journal Watch Women's Health July 26, 2007

Citation(s):

Ronco G et al. Accuracy of liquid based versus conventional cytology: Overall results of new technologies for cervical cancer screening: Randomised controlled trial. BMJ 2007 Jul 7; 335:28.

• Original article (Subscription may be required)
• Medline abstract (Free)