The usefulness of cytodiagnosis and DNA cytometry on nasopharyngeal brush smears for the diagnosis of nasopharyngeal carcinoma.

Abstract

To assess the usefulness of combining cytodiagnosis and DNA cytometry on nasopharyngeal brush samples for the detection of nasopharyngeal carcinoma (NPC). DNA ploidy analysis was undertaken on 66 nasopharyngeal brush samples that had been previously evaluated cytologically. Cytodiagnosis and ploidy analysis demonstrated a sensitivity of 66% and 55%, respectively. Both techniques had a specificity of 100% for NPC cases that were histologically confirmed. The negative predictive values for cytodiagnosis and ploidy analysis were 29% and 24%, respectively. The sensitivity and specificity for cytodiagnosis were not improved by the addition of DNA ploidy analysis. Furthermore, combining the two techniques did not confer any significant advantage compared with the use of cytology and DNA ploidy alone. The relatively low negative predictive values are a significant limitation, and combining cytodiagnosis and ploidy analysis on nasopharyngeal brush samples cannot be recommended for the detection of NPC.