Liquid-based cytology in diagnosing nasopharyngeal carcinoma

Background: Liquid-based cytology (LBC) has achieved great success in cytological diagnosis of various cancers when compared with conventional smear methods, However, its application in diagnosing nasopharyngeal carcinoma (NPC) has never been studied. Methods: Eighty-four consecutive patients who underwent nasopharyngeal biopsy for suspicious NPC or a nasopharyngeal mass under nasopharyngoscopy were enrolled in this prospective study. Brush samples were taken from the same site before punch biopsy and processed with the Thin Prep test. Results: The adequacy, accuracy, sensitivity, specificity, false-negative rate, and false-positive rate of LBC in diagnosing NPC were 92.9% (78 of 84), 93.6% (73 of 78), 84.2% (16 of 19), 96.6% (57 of 59), 15.8%, (three of 19), and 3.4% (two of 25), respectively. There were four inadequate specimens from patients with NPC and two inadequate ones from those without NPC. Conclusions: Our study showed that the adequacy, accuracy, sensitivity, specificity, and diagnostic rate of LBC were equivalent to those using conventional smear methods. Although the diagnostic rate of NPC was lower using brush cytology than by punch biopsy, further improvements in the sampling technique could make brushing cytology a potential tool for NPC screening. (Am J Rhinol Allergy 23, 422-425, 2009; doi: 10.2500/ajra.2009.23.3341)