The light at the end of the tunnel? Can light-based tests increase the accuracy of our diagnoses of pre-cancerous/cancerous lesions?

Study selection Two electronic databases (Medline/PubMed and Embase) were searched up to 30 August 2020. Selected papers fitted the following criteria: human studies published in the English language that assessed adult patients over the age of 18 with a presumptive diagnosis of an oral potentially malignant disorder, oral cancer or oropharyngeal cancer. The studies compared either visual inspection or light-based tests with diagnostic biopsy of the lesions. The outcome measures identified were: sensitivity, specificity, summary receiver operating characteristic curve (SROC), positive predictive value (PPV) and negative predictive value (NPV).Data extraction and synthesis The extraction of data followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline process. Two independent reviewers selected articles via PubMed search, and a further two independent reviewers selected articles via an Embase search. The quantitative data obtained from each study was used to create a database that recorded information on sensitivity, specificity, accuracy, PPV and NPV. Additionally, the value of true positive (VP), false positive (FP), true negative (VN) and false negative (FN) were extracted from each study. In cases where these were not reported, an estimate was calculated. The quality of diagnostic precision studies (QUADAS-2) tool was used to rate the quality of studies as high, unclear, or low.Results A total of 40 papers were ultimately included within the meta-analysis with 5,562 samples of autofluorescence, 1,353 samples of chemiluminescence and 1,892 samples of clinical examination. The majority of the studies evaluating chemiluminescence used the ViziLite technique while most of the studies evaluating autofluorescence used the VELscope. The QUADAS-2 pointed to most of the studies included in this review being of good quality. Clinical examination had the highest specificity (0.78-95% CI [0.65-0.87]) for declaring mucosa to be normal in the absence of dysplasia and malignancy, but had the lowest sensitivity (0.63-95% CI [0.45-0.78]) of actually diagnosing sinister lesions. Autofluorescence more accurately identified premalignant and malignant changes (sensitivity = 0.86 95% CI [0.77-0.91]) compared with chemiluminescence (sensitivity = 0.67 95% CI [0.38-0.87]) and visual examination (sensitivity = 0.63 95% CI [0.45-0.78]). Autofluorescence was also faster and simpler to use compared with chemiluminescence.Conclusions This review and meta-analysis concludes that autofluorescence has greater accuracy in identifying premalignant and early neoplastic changes compared with clinical examination and chemiluminescence. Biopsy remains the gold standard for definitive diagnosis of oropharyngeal and oral premalignant and malignant conditions.