“Comparison of SurePath® liquid-based Pap test to Conventional Pap test in a Multi-site Direct-to-Vial Study”
M Fremont-Smith, J Marino, B Griffin, L Spencer, D Bolick,
Cancer Cytopathology; October 25,2004, Vol 102(5), pp. 269-279.
Split-sample clinical trials for liquid-based Papanicolaou (Pap) smears demonstrated that the liquid-based Pap smear was a safe and effective replacement for the conventional Pap smear. However, clinical intended use of liquid-based technology employs direct-to-vial collection methods. The current study compared the cytologic detection rates of the liquid-based Pap smear with conventional Pap smears in a direct-to-vial study performed at three clinical sites.
Data from 58,580 prospective SurePath® slides and 58,988 historic conventional slides were collected. Results were statistically compared with regard to disease prevalence and adequacy to include biopsy follow-up data for conven- tional and SurePath® Pap tests.
The SurePath® method was found to provide a statistically significantly greater detection rate for clinically important categories of high-grade squamous intraepithelial lesion (HSIL+) and low-grade squamous intraepithelial lesion (LSIL+) (64% and 107%, respectively; P <0.00001 for each lesion) compared with conventional slides. The clinical significance of increased cytologic detection using SurePath® was supported by biopsy data that essentially demonstrated concordance with regard to biopsy interpretation for HSIL+ (P = 0.9105 at Site 1; P = 1.0000 at Site 2; and P = 1.0000 at Site 3) and LSIL (P = 0.6966 at Site 1; P = 0.8052 at Site 2; and P = 1.00 at Site 3). The detection rate of atypical squamous cells of undetermined significance (ASCUS) was found to be significantly increased (75.12%; P < 0.00001). A statistically significantly lower proportion of unsatisfactory slides using the SurePath® test compared with conventional slides was noted (-58%; P 0.00001). The ASCUS/LSIL ratio was found to be reduced overall when using SurePath® (-28.9%), regardless of whether the study sites were combined or considered individually. The rate of false-negative results noted with SurePath® (10.43%) and conventional slides (12.97%) was essentially equivalent.
The SurePath® Pap test was found to outperform conventional slides in the detection of HSIL+ and LSIL+ cytologic lesions of the cervix and reduced the number of unsatisfactory diagnoses. The HSIL+ advantage for SurePath® is not limited to HSIL but appears to extend to carcinoma as well.