Utility of Cell-Block of Bronchial Washings in Diagnosis of Lung Cancer- A Comparative Analysis with Conventional Smear Cytology.

Abstract

Bronchoscopy is a safe & effective means of diagnosing bronchogenic carcinoma with a varying diagnostic yield of different bronchoscopic procedures. Cell-Block (CB) preparation of cytology specimen has been shown to increase the diagnostic yield further. To the authors' knowledge, the diagnostic value of CB as an adjunct to conventional smear cytology (CS) of bronchial washing specimens in the detection of bronchogenic carcinoma has not been well evaluated. The present study was aimed to evaluate the diagnostic utility of CB of bronchial washings when compared with CS. A total of 104 patients of suspected bronchogenic carcinoma were subjected to bronchoscopy as per British Thoracic Society (BTS) protocol. Bronchial biopsy, brushings and washings were collected. Smears were prepared immediately of bronchial washings and another aliquot was subjected to CB preparation and further processing by paraffin embedding and H&E staining. Out of 104 patients, 92 were diagnosed by bronchoscopy with a cumulative diagnostic yield of all sampling techniques being 88.46%. Yield of CB of bronchial washings (44.23%) was higher than Bronchial washings - conventional smears (36.53%). CB detected additional 8 cases of malignancy where corresponding bronchial washings-conventional smears were negative. Exclusive diagnosis by CB was obtained in 2 cases. Brushings and biopsy confirmed malignancy in 49.03% and 57.69% cases. CB of bronchial washings had a higher yield as compared to corresponding conventional smears. Increase in yield was also noted when CB of bronchial washings was combined with biopsy and compared to bronchial washings- conventional smears combined with biopsy. In limited resource settings, CB preparation is a simple method that increases diagnostic yield of flexible bronchoscopy, is cost effective & hence can be routinely used. The immunohistochemical and molecular studies are possible with CB only, which is a distinct advantage over conventional smears of bronchial washings.