Liquid-based cytology for primary cervical cancer screening: a multi-centre study

Area of Science:

• Gynecologic Cytopathology
• Cervical Cancer Screening
• Diagnostic Accuracy

Background:

• The conventional Papanicolaou (Pap) smear is a primary method for cervical cancer screening.
• Limitations in conventional Pap smear preparation and interpretation can affect diagnostic sensitivity.
• Advancements in cytology aim to improve the detection of cervical abnormalities.

Purpose of the Study:

• To compare the diagnostic performance of the ThinPrep fluid-based cytology method against the conventional Pap smear.
• To evaluate differences in the detection rates of cervical intraepithelial lesions between the two methods.
• To assess the potential of ThinPrep to optimize cervical cancer screening effectiveness.

Main Methods:

• A six-centre, split-sample study involving 5428 women.
• Cervical samples were used for both conventional Pap smear preparation and ThinPrep slide preparation.
• Blinded screening of slides followed by independent and consensus review of selected cases.
• Statistical analysis using McNemar's test to compare disease detection rates.

Main Results:

• ThinPrep detected 29% more atypical squamous cells of undetermined significance (ASCUS) and 39% more low-grade squamous intraepithelial lesions (LSIL) or more severe lesions (LSIL+) compared to conventional smears (P = 0.001).
• Detection of LSIL increased by 50% and high-grade SIL (HSIL) by 18% with ThinPrep.
• Consensus review confirmed 18% more LSIL+ diagnoses initially detected by ThinPrep (P = 0.041).

Conclusions:

• The ThinPrep Pap Test demonstrates superior accuracy in detecting cervical abnormalities compared to the conventional Pap smear.
• ThinPrep has the potential to significantly improve the effectiveness of primary cervical cancer screening programs.
• The fluid-based cytology method offers advantages in identifying precancerous cervical lesions.