Acetic acid versus toluidine blue as screening tools for oral potentially malignant disorders

Diagnostic adjuncts such as toluidine blue have been investigated as screening tools that improve visual examination of potentially malignant disorders (PMD) and oral cancer. Acetic acid has been reported to be of value in the early detection of cervical cancers. This study assessed the utility of 5% acetic acid as a diagnostic adjunct in oral PMD and compared the accuracy of acetic acid with toluidine blue in the detection of dysplastic PMD and high-risk lesions.

This cross-sectional study was conducted at a dental hospital in a rural setting. Thirty-one patients with oral PMD formed the study group. Five percent acetic acid was applied to the lesions, followed by toluidine blue application and biopsy. Sensitivity, specificity, and positive and negative predictive values were computed considering true positives as stain uptake in dysplastic and high-risk PMD.

The sensitivity, specificity, and positive and negative predictive values of acetic acid for identifying dysplastic or malignant lesions were 100%, 13.3%, 51.2%, and 100%, respectively, and that for toluidine blue were 75%, 100%, 100%, and 78.9%, respectively. The corresponding values for identifying high-risk PMD (lesions with moderate and severe dysplasia) using acetic acid were 100%, 9.1%, 25.9%, and 100%, respectively, and for toluidine blue were 85.7%, 81.8%, 60%, and 94.7%, respectively.

The utility of acetic acid in detecting dysplasia and high-risk PMD is severely limited due to its poor specificity. Compared with acetic acid, toluidine blue is a superior screening tool.