An improved algorithm using a Health Canada-approved DNA-image cytometry system for non-invasive screening of high-grade oral lesions

BACKGROUND

DNA-image cytometry (DNA-ICM) is able to detect gross alterations of cellular DNA-content representing aneuploidy, a biomarker of malignancy. A Health Canada-approved DNA-ICM system, ClearCyte^® in combination with a cytopathologist's review, has demonstrated high sensitivity (89%) and specificity (97%) in identifying high-grade oral lesions. The study objective was to create an improved automated algorithm (iClearcyte) and test its robustness in differentiating high grade from benign reactive oral lesions without a cytopathologist's input.

METHODS

A set of 214 oral brushing samples of oral cancer (n = 92), severe dysplasia (n = 20), reactive lesions (n = 52), and normal samples (n = 50) were spun down onto slides and stained using Feulgen-Thionin reaction. Following ClearCyte^® scan, nuclear features were calculated, and nuclei categorized into "diploid," "hyperdiploid," "tetraploid," and "aneuploid" DNA ploidy groups by the ClearCyte^® software. The samples were randomized into training and test sets (70:30) based on patient's age, sex, tobacco use, and lesion site risk. The training set was used to create a new algorithm which was then validated using the remaining samples in the test set, where sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated.

RESULTS

The proposed iClearCyte algorithm (>1 "aneuploid" cell or ≥ 1.7% combined "hyperdiploid" and "tetraploid" nuclei frequency) identified high-grade samples with sensitivity, specificity, PPV, and NPV of 100.0%, 86.7%, 89.7%, and 100.0%, respectively, in the test set.

CONCLUSION

The iClearCyte test has potential to serve as a robust non-invasive automated oral cancer screening tool promoting early oral cancer detection and decreasing the number of unnecessary invasive biopsies.

DNA aneuploidy with image cytometry for detecting dysplasia and carcinoma in oral potentially malignant disorders: A prospective diagnostic study

BACKGROUND

Current evidence on diagnostic value of aneuploidy with DNA image cytometry (ICM) using brushings for oral potentially malignant disorders (OPMD) is limited by sample size and inconsistent classification criteria of aneuploidy. This study aimed to explore the optimal cut-off values of DNA content and evaluate the diagnostic accuracy of DNA-ICM for detecting dysplasia and/or carcinoma in OPMD.

MATERIALS AND METHODS

A total of 401 consecutive patients with OPMD were enrolled in this prospective diagnostic study. Brushing and biopsy sample form each patient was processed by DNA-ICM and histological examination respectively.

RESULTS

When the optimal cut-off of at least one aneuploid cell with DNA index (DI) ≥2.3, the area under the curves (AUC) was 0.735 and positive predictive value was 92.7% for detecting dysplasia within OPMD. When the optimal cut-off of at least one aneuploid cell with DI ≥ 3.5, the AUC was 0.851 and negative predictive values was 96.8% for detecting carcinoma within OPMD. Importantly, multivariate analysis revealed that aneuploidy with DI ≥ 2.3 in OPMD was significantly associated with dysplasia risk (adjusted OR, 5.52; 95%CI, 2.90-10.51; P < .001), and aneuploidy with DI ≥ 3.5 in OPMD was strongly associated with malignant risk (adjusted OR, 21.05; 95%CI, 9.34-47.41; P < .001).

CONCLUSIONS

This largest-scale diagnostic study optimized the criteria of aneuploidy cytology for noninvasive detection of oral dysplasia and carcinoma within OPMD. DNA aneuploidy in OPMD was an independent marker that strongly associated with oral dysplasia/carcinoma. Our findings suggest that DNA-ICM may serve as a useful noninvasive adjunctive tool for oral cancer and OPMD screening.

Meta-analysis of two computer-assisted screening methods for diagnosing oral precancer and cancer

The early diagnosis of oral precancer and cancer is crucial and could have the highest impact on improving survival rates. A meta-analysis was conducted to compare the accuracy between the OralCDx brush biopsy and DNA-image cytometry in diagnosing both conditions. Bibliographic databases were systematically searched for original relevant studies on the early diagnosis of oral precancer and oral cancer. Study characteristics were evaluated to determine the accuracy of the two screening strategies. Thirteen studies (eight of OralCDx brush biopsy and five of DNA-image cytometry) were identified as having reported on 1981 oral mucosa lesions. The meta-analysis found that the area under the summary receiver operating characteristic curves of the OralCDx brush biopsy and DNA-image cytometry were 0.8879 and 0.9885, respectively. The pooled sensitivity, specificity, and diagnostic odds ratio of the OralCDx brush biopsy were 86% (95% CI 81-90), 81% (95% CI 78-85), and 20.36 (95% CI 2.72-152.67), respectively, while these modalities of DNA-image cytometry were 89% (95% CI 83-94), 99% (95% CI 97-100), and 446.08 (95% CI 73.36-2712.43), respectively. Results of a pairwise comparison between each modality demonstrated that specificity, area under the curve (AUC), and Q(∗) index of DNA-image cytometry was significantly higher than that of the OralCDx brush biopsy (Z=2.821, p<0.05; Z=1.711, p<0.05; Z=1.727, p<0.05), but no significant difference in sensitivity was found (Z=1.520, p>0.05). In conclusion, the meta-analysis of the published studies indicated that DNA-image cytometry is more accurate than the OralCDx brush biopsy in diagnosing oral precancer and oral cancer.

Evaluation of ploidy status using DNA-image cytometry of exfoliated mucosal cells in oral lichen planus

Background:

Oral lichen planus (OLP) is one of the potentially malignant disorders (PMDs) with a malignancy rate of 0.2-2%. Aneuploidy is considered to be one of the important markers for malignant transformation and DNA-image cytometry (DIC) has been successfully employed in oral mucosal PMDs and also in tumors of the cervix, lung and biliary tract.

Aims:

In this study, we intend to assess the ploidy status of exfoliated cells in OLP using DIC.

Materials and Methods:

Exfoliated cells from 48 patients with different subtypes of OLP (reticular, plaque type, erosive and atrophic) and 10 controls were stained using Feulgen reaction and assessed for integrated optical density using image analysis software and the ploidy status was assessed.

Results:

All the patients in the control group and most of the patients (93.5%) who had reticular or plaque type of OLP (29 out of 31) exhibited diploid nuclei in the smears, whereas 11 patients who had erosive or atrophic types of OLP showed aneuploid nuclei.

Conclusions:

The patients with erosive or atrophic types of OLP are at more risk and assessment of ploidy status by exfoliative cytology can be used as an adjuvant for diagnosis.