Recent advances in thin-layer cytology.

In recent years liquid-based cytology has emerged as an alternative to conventional cytopreparatory methods. In particular, the ThinPrep system has found broad acceptance in non-gynecologic cytopreparation. Many laboratories have successfully applied this technique to body fluids (e.g. urine, pleural effusions), brushing samples (e.g. gastrointestinal tract, lung) and fine-needle aspiration. Most comparative studies have shown the ThinPrep system to perform as well as or better than conventional preparations in nongynecologic cytology; plus, the residual cells within the vial can be used for DNA analysis or immunohistochemical and other special studies. Recently, the ThinPrep 2000 system has been approved for use in gynecologic cytology. This approval was based on a large, multicenter clinical study that showed the ThinPrep system to be favored over the conventional Pap smear for the detection of low-grade squamous intraepithelial lesions, or more severe lesions. At screening centers the improved rate of detecting low grade squamous intraepithelial lesions (LSIL) or more severe diagnosis was up to 73%, with an average improvement of 65% as compared to the conventional Pap smears. Also, for specimen adequacy, the ThinPrep method was statistically favored over conventional cytology methods. This multicenter clinical trial demonstrates the ThinPrep 2000 system was more effective than the conventional Pap smear for the detection of atypical cells and cervical cancer and its precursor lesions. In addition, by collecting cells in a liquid-based medium the opportunity is present to improve the Pap test by adjunctive testing for Human Papilloma Virus or other procedures. This creates the opportunity for improved triage and management of patients with cervical abnormalities.