Evaluation of Liquid Based Cytology for Tongue Squamous Cell Carcinoma: Comparison with Conventional Cytology

Abstract

Oral exfoliative cytology is now used by general practitioners in Japan to screen for oral cancer. With conventional cytology, however, the number of cells that can be sampled is small. Moreover, cell deformation and piling of cells when preparing specimens has been reported. The purpose of this study was to compare conventional and liquid based cytology (LBC), which has been employed with increasing frequency in recent years. We believe that identifying potential pitfalls in oral exfoliative cytology will help improve diagnostic accuracy. A total of 153 patients with tongue squamous cell carcinoma who were diagnosed and treated initially at our hospital between January 2000 and December 2010 were included. Of these, 124 underwent conventional cytology, while the remaining 29 underwent LBC. Histopathological and clinical findings were used as criteria. Conventional cytology yielded a positive rate of 54.8% and LBC 79.3%, while values of 28.2% and 13.8% were obtained for a suspected positive rate, respectively. Liquid based cytology yielded a significantly higher percentage of accurate diagnoses and fewer suspected positives (p<0.05) in cases clinically classified as endophytic and those classified as ulcerative in terms of clinical growth pattern. No significant difference was observed between conventional cytology and LBC in cases of an infiltrative growth pattern, however. The present results suggest that LBC is superior to conventional cytology in achieving an accurate diagnosis based on oral exfoliative cytology. The present findings also suggest that exophytic type, and especially leukoderma type clinical growth patterns constitute pitfall cases in oral exfoliative cytology.

Analysis of false-negatives in exfoliative cytology in oral potentially malignant disorders: A retrospective cohort study

“…Previous OEC studies have shown that poor sampling may lead to a lower diagnostic accuracy. Generally, most dysplastic lesions arise in the basal and parabasal layer initially, and in most cases, the oral mucosa is well-differentiated superficially in the form of keratinization; therefore, the collection of deep-seated cells is crucial for accurate diagnosis using OEC [8,12]. However, low-grade lesions, especially those with strong keratinization, make collection of deepseated cells challenging [8,10,12].…”

“…There are many reports on the accuracy of OEC, including studies in high prevalence and high-grade populations. Generally, the accuracy of OEC was 70−90%, and the sensitivity and specificity were similar [1,[8][9][10]12,13].…”

“…Previous studies have shown that oral exfoliative cytology (OEC) is a useful screening method for oral neoplasms and epithelial dysplasia [1,8−12]. The demand for OEC has increased in recent years due to the ease of cell collection, possibility of direct visualization, and low invasiveness [1,9,10,12]. Early oral epithelial dysplasia has few subjective symptoms and often exists for a long time before it is diagnosed [1,9].…”

“…Previous studies have shown that the presence of keratinized lesions lead to sampling errors and decreased accuracy [1,8,9,12]. Reducing false-negative (FN) is crucial for preventing the occurrence of unexpected oral malignant diseases.…”

Novel cytological model for the identification of early oral cancer diagnostic markers: The carcinoma sequence model

“…Liquid-based cytology (LBC) is a non-invasive technique that can be used for the early diagnosis of OSCC. LBC has higher diagnostic accuracy than conventional cytology; moreover, gene expression analysis and immunocytochemistry (ICC) can be performed on the residual LBC specimens ( 7 – 11 ). There are several reports on ICC and gene expression analysis; however, none of the studies have reported the continuous changes in morphology and the gene and protein expression during carcinogenesis.…”