Diagnostic adjuncts on oral cancer and precancer: an update for practitioners

Genetic linkage analysis of head and neck cancer in a Spanish family

OBJECTIVES

To describe the genetic variants that may be associated with the development of head and neck cancer (HNC) and functionally validating the molecular implications.

MATERIALS AND METHODS

A prospective observational study was carried out on a family of 3 generations in which 3 members had developed HNC. Peripheral blood sample was taken in a routine procedure for exome sequencing in one relative and genotyping in the remaining twelve relatives. For the functional analysis all-trans retinoic acid (atRA) was extracted from saliva and serum and measured using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The presence of HPV-DNA.

RESULTS

None of the patients smoked or consumed alcohol. The presence of HPV DNA was not detected in any of the biopsied samples. A total amount of 6 members out of 13 (46.15%) carried out the same mutation of CYP26B1 (2p13.2; G>T). The mean plasma concentration of atRA was 3.3109 ± 1.4791 pg/mL for the study family and 4.7370 ± 1.5992 pg/mL for the controls (p = 0.042).

CONCLUSION

Lower levels of atRA were confirmed in the study family, which may open the way to the possible relationship between the polymorphism CYP26B1 (2p13.2; G>T) and HNC.

Developing an Algorithm for Discriminating Oral Cancerous and Normal Tissues Using Raman Spectroscopy

The aim of this study was to investigate the clinical potential of Raman spectroscopy (RS) in detecting oral squamous cell carcinoma (OSCC) in tumor and healthy tissues in surgical resection specimens during surgery. Raman experiments were performed on cryopreserved specimens from patients with OSCC. Univariate and multivariate analysis was performed based on the fingerprint region (700–1800 cm−1) of the Raman spectra. One hundred thirty-one ex-vivo Raman experiments were performed on 131 surgical resection specimens obtained from 67 patients. The principal component analysis (PCA) and partial least square (PLS) methods with linear discriminant analysis (LDA) were applied on an independent validation dataset. Both models were able to differentiate between the tissue types, but PLS–LDA showed 100% accuracy, sensitivity, and specificity. In this study, Raman measurements of fresh resection tissue specimens demonstrated that OSCC had significantly higher nucleic acid, protein, and several amino acid contents than adjacent healthy tissues. The specific spectral information obtained in this study can be used to develop an in vivo Raman spectroscopic method for the tumor-free resection boundary during surgery.

Comparing the efficacy of chemiluminescence with lugol's iodine versus toluidine blue in the diagnosis of dysplasia in tobacco associated oral lesions - A diagnostic study

Background

Chemiluminescence is the production of light as a result of a chemical reaction. Oral potentially malignant disorders (OPMDs) include both precancerous lesions and conditions that carry an increased risk of cancer. There are different etiological and risk factors for OPMDs such as smoking, alcohol consumption, infections such as viral and fungal, sun exposure and certain other genetic factors. The most common etiological factor for OPMDs is tobacco usage. Chemiluminescence is a light-based detection system and is very useful for detecting OPMDs for early intervention. Because it is a non-invasive procedure, it can be used to evaluate dysplastic changes in various OPMDs at their initial stage for timely intervention. Vital staining has also been used as a chair-side marker for delineating normal and dysplastic oral mucosal tissues.

Aim

To compare the efficacy of chemiluminescence with Lugol's iodine to that with toluidine blue in diagnosing dysplastic changes in tobacco associated oral lesions.

Methodology

A total of 84 patients with clinically suspicious oral mucosal lesions and OPMDs with tobacco habit history were included and randomly assigned to either of the diagnostic study groups (Group A: chemiluminescence with Lugol's iodine or Group B: chemiluminescence with toluidine blue). All these patients were subjected to a histopathological examination (reference standard).

Results

The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and receiver operating characteristics (ROC) were 91.7%, 66.7%, 84.6%, 80%, and 0.792 for chemiluminescence with Lugol's iodine group (P = 0.001) respectively whereas for chemiluminescence with toluidine blue, the sensitivity, specificity, PPV, NPV and ROC were 100%, 60%, 93.3%, 100% and 0.800 (P = 0.002), respectively.

Conclusion

The combination of chemiluminescence with toluidine blue had a better diagnostic efficiency in detecting dysplasia in tobacco-associated oral lesions when compared to the group of chemiluminescence with Lugol's iodine.

Recent advances in point-of-care diagnostics for oral cancer

Early-stage diagnosis is a crucial step in reducing the mortality rate in oral cancer cases. Point-of-care (POC) devices for oral cancer diagnosis hold great future potential in improving the survival rates as well as the quality of life of oral cancer patients. The conventional oral examination followed by needle biopsy and histopathological analysis have limited diagnostic accuracy. Besides, it involves patient discomfort and is not feasible in resource-limited settings. POC detection of biomarkers and diagnostic adjuncts has emerged as non- or minimally invasive tools for the diagnosis of oral cancer at an early stage. Various biosensors have been developed for the rapid detection of oral cancer biomarkers at the point-of-care. Several optical imaging methods have also been employed as adjuncts to detect alterations in oral tissue indicative of malignancy. This review summarizes the different POC platforms developed for the detection of oral cancer biomarkers, along with various POC imaging and cytological adjuncts that aid in oral cancer diagnosis, especially in low resource settings. Various immunosensors and nucleic acid biosensors developed to detect oral cancer biomarkers are summarized with examples. The different imaging methods used to detect oral tissue malignancy are also discussed herein. Additionally, the currently available commercial devices used as adjuncts in the POC detection of oral cancer are emphasized along with their characteristics. Finally, we discuss the limitations and challenges that persist in translating the developed POC techniques in the clinical settings for oral cancer diagnosis, along with future perspectives.

Narrow band imaging observed oral mucosa microvasculature as a tool to detect early oral cancer: an Indian experience

BACKGROUND

Narrow band imaging (NBI) is a novel method with the potential to improve the diagnostic capability of white-light.

METHODS

A prospective observational study of 50 consecutive patients, with suspicious malignant/premalignant lesions. White-light images were assessed as suspicious for malignancy/negative for malignancy, whereas NBI images were classified based on the IPCL patterns. All lesions underwent biopsy and accuracy was compared with the histopathology (Fig. 1). Fig. 1 Representative images of the IPCL patterns from Types I-IV RESULTS: 25 lesions (49%) were positive for malignancy, 2 (3.9%) lesions showed severe dysplasia, and 24(47%) were considered negative on histopathology. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of white light and NBI in detecting invasive carcinoma was 74.07%, 79.17%, 80.00%, 73.08% and 76.47%, and 92.67%, 90.16%, 92.56%, 91.67% and 92.16% respectively. The NBI group had a significantly better sensitivity and specificity to white light. The interobserver concordance was κ = 0.881.

CONCLUSION

NBI is a highly effective tool to detect invasive carcinomas amongst suspicious lesions of the oral cavity.

Abrasive cytohistology of squamous epithelial lesions

Objective:

To describe a method to retrieve cellular and tissue elements of oral squamous epithelium obtained by abrasive methods and to conduct investigations by cytohistology.

Method:

We developed a special gelatine pocket suitable for paraffin embedding of sparse material obtained from brush biopsies (BBs). This was subjected to combined evaluation of a cytological (smear) and histological examination of the ‘tissue sections’ – referred as cytohistology. Four diagnostic categories were applied for evaluation. Other special diagnostic methods were also applied in addition to recording dysplasia.

Results:

A total of 51, 755 BBs from suspicious lesions of the oral mucosa (mostly oral potentially malignant disorders – OPMD) were evaluated for the presence of carcinoma or dysplasia; in all, 1.7% were positive, 78.2% were negative for any epithelial atypia, 16.8% atypical and 3.3% inadequate. All BBs also had cytohistological evaluation. A ‘positive’ diagnosis by cytohistology was a reliable indicator of dysplasia or carcinoma, requiring further incisional/excisional biopsy. In the ‘atypical’ category, a variety of lesions were found, about half being dysplasia or carcinoma. This category challenges the clinician for further clinical, therapeutic and/or excisional examination. In ‘negative’ cases with persistence of the lesion, a re-examination in 1-year sequence is recommended.

Conclusion:

Cytohistology of material derived by abrasive methods allows earlier detection of dysplasia/carcinoma. A number of additional oncological and non-oncological findings make this method a valuable non-invasive diagnostic procedure for oral mucosal lesions.

Comparative evaluation of autofluorescence imaging and histopathological investigation for oral potentially malignant disorders in Taiwan

OBJECTIVES

Autofluorescence imaging is gaining popularity as an adjunctive test for oral potentially malignant disorders (OPMD). This study evaluated the efficacy of autofluorescence imaging based on the current standard oral mucosal disorder checklist in Taiwan.

MATERIALS AND METHODS

In total, 126 patients suspected to have mucosal disorders at the Division of Oral and Maxillofacial Surgery, Tri-Service General Hospital, Taipei, Taiwan, were enrolled. Following a conventional oral examination by using the oral mucosal disorder checklist and an autofluorescence imaging examination, all participants underwent histopathological examination to access epithelial dysplasia.

RESULTS

Among 126 patients, 68 patients were diagnosis as having an OPMD and 63 having epithelial dysplasia. Autofluorescence imaging exhibited a sensitivity, specificity, positivity predictive value (PPV), negative predictive value (NPV), and accuracy of 77.94%, 35.42%, 63.10%, 53.13%, and 60.34%, respectively, for OPMD and of 88.89%, 43.86%, 63.64%, 78.13%, and 67.50%, respectively, for epithelial dysplasia. After the exclusion of 48 non-OPMD cases according to the checklist, the sensitivity, specificity, PPV, NPV, and accuracy of autofluorescence imaging became 87.50%, 72.73%, 94.23%, 53.33%, and 85.07%, respectively, for epithelial dysplasia.

CONCLUSION

The efficacy of epithelial dysplasia identification and OPMD risk assessment can be increased after the exclusion of the non-OPMD cases through autofluorescence imaging.

CLINICAL RELEVANCE

Autofluorescence imaging is a useful adjunct that can assist specialists in assessing OPMD patients prone to dysplasia without compromising patient care.

A Real-Time Near-Infrared Fluorescence Imaging Method for the Detection of Oral Cancers in Mice Using an Indocyanine Green-Labeled Podoplanin Antibody

Podoplanin is distinctively overexpressed in oral squamous cell carcinoma than oral benign neoplasms and plays a crucial role in the pathogenesis and metastasis of oral squamous cell carcinoma but its diagnostic application is quite limited. Here, we report a new near-infrared fluorescence imaging method using an indocyanine green (ICG)-labeled anti-podoplanin antibody and a desktop/a handheld ICG detection device for the visualization of oral squamous cell carcinoma-xenografted tumors in nude mice. Both near-infrared imaging methods using a desktop (in vivo imaging system: IVIS) and a handheld device (photodynamic eye: PDE) successfully detected oral squamous cell carcinoma tumors in nude mice in a podoplanin expression-dependent manner with comparable sensitivity. Of these 2 devices, only near-infrared imaging methods using a handheld device visualized oral squamous cell carcinoma xenografts in mice in real time. Furthermore, near-infrared imaging methods using the handheld device (PDE) could detect smaller podoplanin-positive oral squamous cell carcinoma tumors than a non-near-infrared, autofluorescence-based imaging method. Based on these results, a near-infrared imaging method using an ICG-labeled anti-podoplanin antibody and a handheld detection device (PDE) allows the sensitive, semiquantitative, and real-time imaging of oral squamous cell carcinoma tumors and therefore represents a useful tool for the detection and subsequent monitoring of malignant oral neoplasms in both preclinical and some clinical settings.