Oral Cancer Screening: Targeting High-Risk South Asian Populations in the United Kingdom

Abstract

South Asians residing in the UK are known to be significantly different in terms of socio-economic and cultural influences from the UK population in general. They are at substantially higher risk of developing oral cancer (OSCC) and the potentially malignant disorder (PMD) oral submucous fibrosis (OSF). To overcome barriers to conventional health service use, a mobile dental unit was the base for screening within the South Asian community. Bilingual advocates ensured cultural acceptability and actively recruited high-risk individuals for screening as well as being involved at the secondary referral centre to facilitate attendance for definitive diagnosis of positive screened individuals. In total 1596 high-risk individuals were screened and 5.4% referred with suspicious lesions. No OSCC was detected in any positive screened individuals but PMDs were confirmed in 29%, with dysplasia (15%) and OSF (9%) the commonest lesions referred. Due to the complex presentation of OSCC the most appropriate gold standard screening outcome is the detection of individuals who cannot be discharged from long-term follow-up at the secondary referral centre. On this basis screening specificity was 99% and Positive Predictive Value (PPV) 79%. The low PPV was attributed to the high prevalence of complex oral mucosal lesions (46%) that cannot be definitively diagnosed as benign by visual examination alone, which indicates diagnostic aids are required for screening this high-risk population. 4 Compliance with referral for positive screened individuals was only 76% and immediate incisional biopsy of positive screened individuals would be needed to improve this. In addition to histological detection of dysplasia, molecular markers of disease could readily be investigated by immunohistochemistry and the expression of keratins are ideal candidates due to their responsiveness to pathological signalling and abnormal expression in oral (pre)cancer. Analysis of 28 fresh frozen OSF samples and 6 site-matched controls, using a panel of 22 monoclonal antibodies, revealed changes in keratin 17 expression which correlated with disease severity. A mobile dental unit staffed by suitably experienced dentists and cultural advocates and equipped for immediate histological diagnosis of positive screened individuals is required in order to undertake effective and ethical oral cancer screening in high-risk UK based South Asian populations.