Monitoring Role of Non-invasive Examinations on the Clinical Efficacy of Photodynamic Therapy for Oral Potentially Malignant Disorders.

Objective: To assess the clinical efficacy of 5-aminolaevulinic acid photodynamic therapy (5-ALA-PDT) in treating oral potentially malignant disorders (OPMDs) and investigate the utility of toluidine blue staining and autofluorescence examination for monitoring the efficacy of 5-ALA-PDT.

Methods: A prospective cohort study was conducted, including 75 OPMDs patients who underwent 5-ALA-PDT and follow-up observation. The patients' lesion size and clinical presentation were recorded to evaluate the clinical efficacy of 5-ALA-PDT. Toluidine blue staining and autofluorescence examination were performed as auxiliary monitoring methods, aiming to assess their diagnostic capabilities as non-invasive examinations for detecting pathological oral epithelial dysplasia (OED) and explore their monitoring value for the clinical efficacy of 5-ALA-PDT.

Results: Toluidine blue staining showed a sensitivity of 62.2% and a specificity of 42.9% for diagnosing OED, whereas autofluorescence examination showed a sensitivity of 67.2% and a specificity of 64.3%. The parallel combination of both examinations increased the sensitivity to 77.0%, whereas the series combination increased the specificity to 71.4%. After 5-ALA-PDT, 38.7% of patients with OPMDs achieved complete remission, with an overall response rate of 92%. Persistent positive toluidine blue staining after 5-ALA-PDT treatment was significantly associated with treatment failure. The clinical efficacy of 5-ALA-PDT gradually decreased in patients with aggravation, stable or improved lesions from non-invasive examinations both before and after treatment.

Conclusion: 5-ALA-PDT demonstrates significant efficacy in treating OPMDs by effectively eliminating lesions. Toluidine blue staining and autofluorescence examination have certain diagnostic capabilities for OED and can be used for monitoring efficacy during 5-ALA-PDT treatment.