Evaluation of nuclear morphometry and DNA ploidy status for detection of malignant and premalignant oral lesions: quantitative cytologic assessment and review of methods for cytomorphometric measurements

Abstract

Purpose: Detection of a precancerous or cancerous lesion when small is one of the most important factors to improve 5-year survival rates of oral cancer. Although surgical biopsy is the most definitive method for diagnosing oral lesions, it is impractical to routinely subject large numbers of patients to biopsy. Recently, cytomorphometric assessments improved by advanced computer-assisted image analysis systems have gained importance. This study was established to evaluate the efficacy of nuclear cytomorphometric analysis and DNA ploidy status for the detection of oral malignancies. Methods used for cytomorphometric analysis were also reviewed.

Patients and methods: Oral mucosal smears (n = 44) were obtained from patients (n = 22) presenting with various oral lesions using a cytobrush immediately before biopsy. Cytomorphometric measurements and nuclear Feulgen DNA content analysis were carried out after the Feulgen staining procedure. Smears from the lesion site constituted the study group whereas contralateral healthy mucosal sites served as control.

Results: DNA ploidy analysis revealed 20 diploid (90.9%) and 2 aneuploid DNA patterns (9.1%) sampled from the lateral margin of the tongue and floor of the mouth. When only malignant lesions were considered, aneuploidy rate was 16.7% whereas a diploid pattern was indicated for 83.3% of the sample. With cytomorphometric measurements, a statistically significant difference was shown for nuclear perimeter, area, diameter equivalent to circle, minimum and maximum Feret, intensity, DNA content (c) and DNA index values.

Conclusions: Cytomorphometric analysis via oral brush biopsy is a valuable adjunct to biopsy for identification of premalignant and early stage cancerous oral lesions as a rapid and minimally invasive procedure with high specificity and sensitivity rates, requiring no topical or local anesthetic.