Oral cancer screening
Authors: Sloan P. 
Published: September 2007

Oral and oro‐pharyngeal cancer is a global health problem, with over 500 000 new cases diagnosed per annum worldwide. The geographical incidence varies and in parts of in the Indian subcontinent oral cancer constitutes up to 40% of all cancers. Early detection is an essential part of reducing mortality and morbidity.

Our Cochrane systematic review (Kujan et al, Cochrane Database Systematic Review. 2006, 3: CD004150) demonstrated that there is insufficient evidence to include or exclude population screening for oral cancer into healthcare systems. Only one large scale cluster randomized controlled trial has been reported. However the final round of the study showed that is some benefit in visual screening if the high risk group (alcohol, tobacco and paan users) is targeted.

Improved detection of pre‐cancerous oral lesions and clinically inconspicuous cancers can be achieved by improving clinicians’ awareness of suspicious oral lesions and by encouraging a systematic approach to oral examination. Fluorescent instruments (Velscope) and tolonium chloride rinsing can also aid early detection of suspicious oral lesions. At present, all patients with suspicious oral lesions detected by opportunistic dental screening are referred for scalpel biopsy. Non‐attendance following referral for biopsy is a major problem reported in many oral cancer screening studies. Cytology may go some way to solve this problem.

Oral exfoliative cytology using a spatula was widely used in the 1970s but fell out of favour because of the reported high false negative rates. It is likely that false negative results were due to inadequate sampling of keratinizing lesions. Several recent studies have reported that cytobrush collection is superior to spatula use as a sampling method in the oral cavity. High rates of sensitivity and specificity are reported for detection of oral dysplastic cells, enabling patients for whom biopsy is mandatory, to be selected and properly counselled.

A novel cytobrush utilizing ‘thin hair technology’, the Rovers Orcellex® brush, has been devised specifically for oral use and we have evaluated it in 50 normal volunteers using liquid based cytology. Adequate samples can be obtained by rotating the brush ten times against the oral mucosa. Cells from all epithelial layers are obtained. No participants reported experiencing pain and only a few experienced discomfort during sample collection. We found that samples were sufficient for effective immunostaining for p16 and FHIT, as well as high risk HPV detection by PCR. Excellent results were obtained with both SurePath® and ThinPrep® liquid based cytology systems. We are currently building up our experience of the cytological features of oral and oro‐pharyngeal cancers, pre‐cancerous lesions and benign disorders.

A body of evidence is accumulating that suggests that high risk HPV positive head and neck cancers have a greater radiosensitivity and better clinical outcome than their non‐HPV counterparts. Brush collection of fresh cells combined with real time PCR may offer an excellent way to detect integrated HPV in these tumours.

Whilst biopsy will remain as the gold standard for diagnosis, it is likely that brush cytology will be increasingly used for screening, surveillance and for the detection of biomarkers of response and prognosis in established head and neck cancers.