Adjunctive tests cannot replace scalpel biopsy for oral cancer diagnosis

Data sources Medline, the Cochrane Diagnostic Test Accuracy Studies Register, the Cochrane Oral Health Groups Trials Register, Embase and MEDION.
Study selection: Two of the reviewers independently assessed titles abstracts and extracted data. Cross-sectional diagnostic test accuracy studies (or consecutive series) and randomised studies of diagnostic test accuracy that reported the diagnostic test accuracy of vital staining, oral cytology, light-based detection and oral spectroscopy, blood or saliva analysis used as an adjunct to conventional oral examination in detecting PMD or oral squamous cell carcinoma of the lip or oral cavity were considered. Scalpel, punch or fine needle aspiration biopsy with histological diagnosis was the reference test.
Data extraction and synthesis: Study quality was assessed using a modified version of QUADAS-2. Meta-analysis was used to combine the results of studies for each index test using the bivariate approach to estimate the expected values of sensitivity and specificity. Meta-regressionanalysis was undertaken to explore possible sources of heterogeneity.
Results: Forty-one studies, recruiting 4002 patients were included. No single study could be classified as being at low risk of bias across all domains. Fourteen studies evaluated vital staining, 13 studies oral cytology and 13 studies light-based detection or oral spectroscopy, while six studies assessed two combined index tests. There were no eligible diagnostic accuracy studies evaluating blood or salivary sample analysis.
Conclusions: The overall quality of the included studies was poor. None of the adjunctive tests can be recommended as a replacement for the currently used standard of a scalpel biopsy and histological assessment. Given the relatively high values of the summary estimates of sensitivity and specificity for cytology, this would appear to offer the most potential. Combined adjunctive tests involving cytology warrant further investigation.