Efficacy of Rose Bengal in Comparison With Toluidine Blue in Detection of Premalignant Lesions: a Preliminary Study

Introduction Toluidine blue staining is the most common technique used for the early detection of dysplastic changes in patients with premalignant lesions. One meta-analysis of Rosenberg et al. previously published reported sensitivity ranged from 93.5% to 97.8% and the specificity ranged from 73.3% to 92.9%. Zang et al reported that TB not only detects high-grade dysplasia but detects OPLs with minimal or no dysplasia with high-risk clinical and molecular attributes.4 But, studies have shown as high as 30% risk of false-positive staining.

Rose Bengal (RB) has been widely used to diagnose various ocular surface disorders including delineation of the extent of corneal and conjunctival neoplasms. It has been believed to stain desquamated ocular epithelial cells, dead or degenerated cells, or wherever there is poor protection of the surface epithelium by the preocular tear film rather than lack of cell vitality. These characteristic features of RB lead the researchers to apply it in oral premalignant lesions.5 In none of the studies, reliability of RB stains was not compared with existing or previously practiced methods in oral premalignant lesions. Hence this study was undertaken with the aim of comparing the RB and TB stain and for early detection of dysplasia in oral premalignant lesions.

Materials and Methods:

Study group consists of 41 oral premalignant lesions in patients visiting the Department of Oral Medicine and Radiology of The oxford dental college and hospital, Bangalore. Patients with OSMF, patients with bleeding disorders, patient with other systemic diseases were excluded from the study.To perform the present study, ethical clearance was obtained from the Institutional Ethical Board. Study procedure was explained and informed consent was taken from the selected patients with premalignant lesions. The patients with lesions were subjected to detailed case history, intra oral examination and photographs of the lesions were recorded. Patients with habits were counselled to quit the habit and recalled after 2 weeks for staining. Since one patient had not quit the habit in the two weeks from first visit, in another patient the lesion disappeared in two weeks 2 patients (3 lesions) were not included in the study. (Graph1)

Initially patients were asked to rinse their mouth with distilled water for 1 minute. 1% RB solution was applied with a cotton tip for 2 minutes. Again patients were asked to rinse their mouth for 1 minute with distilled water to remove excess RB solution and the area which had taken up the stain was photographed. Following this, patients were asked to rinse their mouth with 1% acetic acid for 1 min to remove the remaining RB stain from the lesion and were prepared for TB staining. 1%Toluidineblue is applied over the lesion and after 30 seconds patients were made to swish with 1% acetic acid and the area stained was recorded photographically.