This systematic review provides a synthesis of autofluorescence visualization devices in the early detection of malignant transformation in oral premalignant and malignant lesions. Several histopathological changes (hallmarks) have been described in the literature for an oral lesion to become malignant. These changes, such as, the acquisition of sustained proliferative signalling, evasion of growth suppressor cells, resistance to cell death, replicative immortality (immortalization), induction of angiogenesis, activation of tissue invasion and metastasis, deregulation of cellular energy metabolism, evasion of immune destruction are difficult/impossible to accurately detect with conventional oral examinations through the naked eye.30–32
Over the past few decades, different biotechnological companies have developed devices (diagnostic tools) that claim to detect the histological changes that occur during carcinogenesis.33–38 When these changes occur, they appear as a LOF or as a dark view during the autofluorescence examination.36,38 Multiple studies have investigated the diagnostic value of using these diagnostic devices to assist in adjunctive diagnosis of oral cancers from OPMDs.33–35,37,39 Despite the technological promise of autofluorescence-based adjunctive diagnostics, our findings suggest that their overall clinical reliability is limited.
From our pooled meta-analysis, the overall sensitivity of autofluorescence devices was estimated at 55.6% (95% CI: 34.6%–74.8%), indicating that almost half of truly malignant or dysplastic lesions could be missed using these tools alone. Similarly, the pooled specificity was 47.7% (95% CI: 29.2%–66.8%), suggesting a mid ability to identify those without the disease, which may lead to unnecessary biopsies, anxiety, and overtreatment. The diagnostic odds ratio (DOR) of 1.77 (95% CI: 1.04–3.47) underscores the modest discriminative power of these tools when compared to the gold standard of histopathology. Additionally, variations in lesion types (e.g., erythroplakia, leukoplakia, verrucous leukoplakia), examiner expertise, device type, light source, and patient demographics (e.g., habits such as tobacco or areca nut chewing) likely contributed to the high heterogeneity (I² = 78.9%) observed across studies. This underlines the need for standardized protocols in clinical assessment and interpretation of autofluorescence findings.
These results align with the current consensus in the literature that autofluorescence tools should not be used in isolation but rather serve as adjuncts to conventional oral examination (COE).34–36, 38–40 For instance, the study by Jain et al. highlighted that while autofluorescence showed improved diagnostic accuracy over white light examination (95% vs. 75.7%)29, the broad variation in sensitivity and specificity among included studies, as evidenced by the wide prediction intervals, suggests that diagnostic performance is highly context-dependent.
The inaccuracies associated with using autofluorescence are described in the literature for lesions with hyperkeratosis or proliferative growths, which can result from additional cellular layers (e.g., keratin).26,41 These additional cellular layers can cause an increase in fluorescence that may conceal dysplastic and/or neoplastic areas, leading to a masked or umbrella effect.42,43 While advancements and alternative autofluorescence tools have emerged to address these shortcomings, diagnostic energy sources must ideally operate within a specific wavelength range (400–460 nm) to ensure optimal interaction with oral tissues.44 While some studies have utilized devices with higher wavelength filters (up to 525nm)44,45, deviations from this range risk inducing oxidative stress and potential cellular damage, underscoring the need for both spectral precision and biological safety in the development of next-generation diagnostic adjuncts.25,45,46
Despite the methodological quality of this systematic review and meta-analysis, it is not without limitations. There is considerable heterogeneity among the studies due to differences in study designs, sample sizes, autofluorescence devices, and variations in population groups, which may limit the generalizability of the findings. Additionally, we did not account for the subjective nature of autofluorescence interpretation, which may lead to operator-dependent variabilities.