A prospective clinical trial evaluating the performance of liquid-based cytology (ThinPrep Pap Test) in the detection of cervical lisions

Abstract

Objective : We compared the performance of “ThinPrep” liquid-based cytology to that of conventional Papanicolaou smears in detecting high-grade squamous lesions (HSIL) of the cervix.
Study Design : Specimens numbering 8,051 split-sample conventional Papanicolaou smears and “ThinPrep” samples obtained with patients’ consent from May 2007 to March 2008 were compared in a matched-pair double-blind study in which cervical samples were collected and a conventional smear prepared Immediately, following which residual cellular material on the sampling device was rinsed into a proprietary preservative fluid and processed using a ThinPrep 2000 processor. Cytological diagnoses and specimen adequacy were classified using the 2001 Bethesda System for cervical cytological diagnosis, and results compared.
Results : Of these samples, 7,498 (93.1%) were negative in colposcopy or biopsy and 553 (6.9%) were positive at CIN2 or more in biopsies. Sensitivity for the detection of CIN2 or more was 71.3% and specificity 99.0% (conventional) compared to sensitivity of 77.4% and specificity of 98.9% for “ThinPrep” samples.
Conclusions : “ThinPrep” was more effective than conventional Pap smears in detecting HSIL or CIN2 and more serious lesions.