| Abstract [eng] |
The study comparing the effectiveness of a novel liquid-based Pap test (the PapSpin) with the conventional Pap smear. The impetus behind the study is meritorious: although the conventional Pap smear has been highly effective in diminishing mortality from cervical cancer, it is not perfect. It suffers from inconsistency in cell thickness and occasional obscuring blood, which hinder accurate evaluation. An alternative preparation method, one that would reduce the amount of blood and provide for a more consistent, thin layer of cells would make screening easiser and more accurate. The several performance characteristics examined in the study: Rate of unsatisfactory smears, rate of \"atypical\" smears (smears with an interpretation of \"atypical squamous cells of undetermined significance\"), sensitivity, specificity, positive predicitve value (PPV), and negative predictive value (NPV), based on histologic correlation and suitability for human papillomavirus (HPV) testing. The study consists of two principal parts. In the first part, the cervical sample collected was split into two preparations (\"split sample\"): a conventional smear was prepared first, then the residue left on the collection device was used to prepare a PapSpin slides. In the second part (\"direct to vial\"), the entire cervical sample was used to prepare a PapSpin slide. In the \"split sample\" study a significant reduction in the proportion of unsatisfactory and \"atypical\" cases was found when slides were prepared using the PapSpin method. There was no significant difference in accuracy (sensitivity, specificity, PPV, NPV) as measured by histologic correlation. The performance characteristics of the PapSpin were similar in the \"direct to vial\" part of the study, although the rate of \"atypical\" cases was higher than in the split sample study. The dissertation also includes an articulate and thorough overview of cervical cytology and related issues, including the epidemiology of cervical cancer and its precursors, a summary of cytomorphology and histomorphology, and HPV testing methods. |
