Comparison of Conventional Smear, Cell Block and Liquid-based Preparation in the Evaluation of Bronchial Washing Specimen in Lung Cancer Patients

Abstract

BACKGROUND: The preparation of conventional smears (CS) from mucoid samples, despite mucolysis, can pose difficulties for cytotechnologists or cytopathologists. In recent years, liquid-based cytology (LBC) devices have been developed in attempts to improve the cytopreparation process. LBC improves both sample collection and sample preparation. Cell block preparations (CB) can be made from residual tissue fluids, and are a useful adjunct to smears.

METHODS: We retrospectively reviewed 3 preparations from 209 patients whose diagnosis was later confirmed via bronchoscopic biopsy, fine needle aspiration, gun biopsy or operation. Each case was categorized into one of three groups: "negative," "atypical or suspicious" and "malignant."

RESULTS: When conflating the "atypical" and "malignant" categories into a "positive" category, the sensitivity of each preparation was 74.4% in LBC, 72.9% in CS, and 76.5% in CB preparations. Specificity was 98.7%, 94.7% and 98.7%, respectively. By combining LBC and CB, the sensitivity is 78.2%.

CONCLUSIONS: Among three different preparation methods, sensitivity is highest in the CB method. LBC has many advantages in evaluating cell morphology and by combining CB method, the sensitivity can be improved slightly. The application of all three methods may prove helpful when one or another method proves diagnostically inconclusive.