Table 2.
Various techniques used for the detection of oral cancer.
|
Sr. No. |
Technique | Principle/Mechanism | Specimen | Biomarker | Sensitivity | Advantages | Disadvantages | Cost (∼₹) | Ref. |
|---|---|---|---|---|---|---|---|---|---|
| 1. | Autofluorescence spectroscopy | Autofluorescence spectroscopy and imaging | Oral tissue | NA | 91.1% | Non-invasive Patient compatible |
Non-specific | 400–1000 | [17] |
| 2. | Brush biopsy | Brushing and microscopic examination | Oral cells | Secretory leukocyte protease inhibitor | 77.0% | Non-invasive Relatively painless Low cost Requires minimum technical skills |
Inadequate sampling False negative results |
500–1500 | [18,19] |
| 3. | Computed tomography | Ionizing radiation (X-ray)-based tissue imaging | Soft tissue in head and neck region (in situ) | NA | NA | Rapid and painless Widely available Decent visualization |
The harm of radiation exposure Lower resolution Side effects of contrast medium |
500–5000 | [20] |
| 4. | Confocal microscopy | Optical imaging | Oral mucosal cells | NA | NA | Control of depth of field Collection of multiple optical sections Elimination of background data |
A limited number of excitation wavelength Harmful high-intensity laser irradiation Expensive |
4000 | [21] |
| 5. | Diffuse reflectance spectroscopy | Tissue reflectance optical spectroscopy | Oral tissue | Collagen, elastin, keratin, FAD, and NADH | 98.5% | Low cost Rapid Non-invasive Quantitative Good sensitivity and specificity Real-time data |
Complex Encompasses several broad and overlapping bands |
500–2000 | [22] |
| 6. | DNA microarray | Simultaneous measurement of multi-gene expression | Oral tissue | Genes i.e. CDH1, MMP3, SPARC, POSTN, TNC, TGM3, HMGA1, PABPC1, NT5E, FASN, FOS, P53, etc. | NA | High throughput technology Relatively affordable High sensitivity |
Laborious method Numerous printing devices are required |
700–5000 | [23,24] |
| 7. | Elastic scattering spectroscopy biopsy | Wavelength dependant light scattering | Oral tissue | NA | 87.0% | Used in deciding the extent of surgical margins No secondary procedures |
Time-consuming Limited angular resolution |
– | [25] |
| 8. | Enzyme assay | ELISA | Saliva | Proteases | NA | Less sample volume Non-invasive |
Laborious method Lower accuracy |
200–1000 | [26] |
| 9. | Exfoliative biopsy | Scraping and microscopic examination | Oral epithelial cell linings | Epidermal growth factor receptor (EGFR) | 100% | Patient Compliant Low cost Minimal skills required Minimal instrumentation |
Chances of contamination and false-negative results Low sensitivity Inadequate sampling |
600–2600 | [27,28] |
| 10. | Fine needle biopsy | Microscopic examination | Oral cells | NA | 75% | Simple Accurate Low cost |
Bleeding Infection Nerve Injury Swelling |
1000 | [29,30] |
| 11. | Fourier transform infrared spectroscopy | Absorption based optical spectroscopy | Sputum | Glycogen, keratin | NA | High sensitivity, specificity, and accuracy Non-invasive Early detection |
Potassium bromide reduces spectral quality | 1800 | [31] |
| 12. | High-performance liquid chromatography (HPLC) | Column chromatography | Serum | Serum proteins | 87.5% | Automated procedure Sample retrieval Quantitative investigation High sensitivity |
Require special detectors Expensive |
4000–5000 | [32] |
| 13. | Histopathological examination | Microscopic examination | Oral tissue | p53, ki-67 | NA | Large segments of tissues are studied Quick collection Little or no risk |
Time-consuming slide preparation Chances of human error Less specific Difficulty to identify specific types of cells |
800–6400 | [33] |
| 14. | Immunohistochemistry | Staining and microscopic examination | Oral tissue | Mutant p53 gene | NA | Widely used Rapid |
No availability of standardized stains Difficult quantification Chances of human error |
1750–3500 | [34] |
| 15. | Incisional biopsy | Microscopic examination | Oral tissue | Cytokeratin-19 | NA | A small piece of tissue is required Performed in suspected cases of malignancy and pre-malignancy Detailed, specific, and accurate analysis |
Increased risk of metastasis of malignant lesions Avoided in vascular cases |
1000–2000 | [35] |
| 16. | Laser capture microdissection | Cell extraction and molecular characterization | Oral tissue | Proteins (CK-14, CK-17) | NA | Accurate and quick cell separation Preserves tissue morphology |
Expensive Sample contamination High level of expertise required |
6000 | [36,37] |
| 17. | Laser-induced tissue auto-fluorescence | Fluorometry | Oral mucosa (in situ) | NADH, elastin, collagen | 100% | High sensitivity Low sample volume Rapid Suitable for in situ testing |
Limited depth of penetration | – | [38] |
| 18. | Liquid biopsy | Molecular biotechnology procedures (e.g. PCR) | Blood, saliva | Circulating tumor cells/DNA, exosomes for blood and Cd63, salivary exosomal miRNAs | 88.9% | Rapid Easy sampling Less invasive Comprehensive tissue profile Allows more frequent and serial samplings over time Allows molecular profiling of tissues |
Need for an initial histological diagnosis Chances of false-negative An expert analyst is required Expensive |
8000-20,000 | [39] |
| 19. | Magnetic resonance imaging | Non-ionizing radio frequency electromagnetic radiation-based analysis | Soft tissue in head and neck region (in situ) | NA | NA | Non-invasive and no radiation High-resolution images Multidimensional imaging Detects status of metastasis |
Expensive Probability of false-positive result Patients with metal implants cannot undergo MRI |
5000–17000 | [40] |
| 20. | Mass spectroscopy | The mass-to-charge ratio of ions is measured with respect to intensity | Oral tissue | Proteins and lipids | NA | Molecular profiling of tissues Accurate |
Expensive instrumentation | 2000–6000 | [41] |
| 21. | Micro total analysis system | Microfluidics | Saliva | Nucleic acids | NA | Rapid Convenient Low cost Portable Low sample volume Non-invasive Automated operation |
Complex fabrication method Insufficient interfaces for fluid transfer |
50–100 | [42] |
| 22. | Multispectral digital microscope | Fluorescence imaging | Oral tissue | NA | 98% | Highly sensitive Informative |
Slow Complex sample preparation |
500–2000 | [43] |
| 23. | Optical coherence tomography | White light Michelson interferometry | Oral mucosa | NA | 90% | High-resolution images Fast acquisition time Non-invasive Easy-to-use |
Limited depth of penetration (1.5–2 mm) Light interference reduces sensitivity Negative influence on image quality due to hyperkeratosis. |
1000–2500 | [44,45] |
| 24. | Physical examination | Systematic visual examination and palpation | Oral cavity (in situ) | NA | NA | Reduces morbidity, mortality, incidence of invasive cancers Identifies high-risk groups Low cost |
Detection in a late phase Requires skilled professional Chances of false positive and negative |
200–500 | [46] |
| 25. | Polymerase chain reaction | DNA amplification | Serum and saliva | HPV DNA, tetranectin | NA | Quantitative Greater sensitivity Reproducibility Better control of quality in the process Lower risk of contamination |
Expert analyst required Analysis depends on many complex, interrelated factors Expensive |
3000–4000 | [47] |
| 26. | Positron emission tomography | Imaging using radioactive agents | Head and neck region (in situ) | NA | NA | Measure cellular-level metabolic changes Early detection Non-invasive |
Less accurate sometimes Short decay-duration of a radioactive substance Expensive |
2000–27000 | [48] |
| 27. | Raman spectroscopy | Optical spectroscopic technique for chemical analysis | Oral tissue | Keratin | 95% | Minimal sample preparation Highly informative Non-destructive Non-invasive |
Signal inadequacy Bands overlap, difficulty in identifying individual component |
1000 | [49,50] |
| 28. | Spectral cytopathology | Micro-spectral measurement and multivariate data analysis | Oral cells | Proteins | NA | Accurate and reproducible Less human error |
Expensive | – | [51] |
| 29. | Ultrasound (Sonography) | High-frequency sound wave-based imaging | Head and neck region (in situ) | NA | NA | Non-invasive Non-ionizing radiation |
Operator dependent analysis Cannot image cyst duct |
600-20,000 | [52] |
| 30. | VELscope | Fluorometry | Oral tissue (in situ) | NA | 74.1% | Assist in biopsy site selection Low cost Non-invasive Easy and rapid Convenient Early diagnosis of lesions |
No recording Provide false positive and false negative No definitive diagnosis Low sensitivity Inadequate sampling |
1000–2000 | [53] |
| 31. | Vital staining techniques | Visual tissue staining (e.g. toluidine blue) and microscopic examination | Oral tissue | Sulfate, DNA, RNA |
97.8% | Simple Low cost Non-invasive Easy-to-do Widely available |
High percentage of false-positive cases | 20–200 | [54] |
| 32. | ViziLite | Tissue reflectance-based examination | Oral soft tissue (in situ) | NA | 77.3% | Non-invasive Easy and rapid Convenient Early detection Low cost |
No recording Low specificity for dysplasia Non-specific |
1000 | [55] |
| 33. | X-ray | Radiation-based imaging | Head and neck region (in situ) | NA | NA | Easy Rapid Non-invasive |
Unsafe for pregnant women No precise and detailed information for each tooth or soft tissues |
250–2000 | [56] |