Perspectives on oral squamous cell carcinoma prevention—proliferation, position, progression and prediction

Abstract

Squamous cell carcinoma arising from oral mucosal epithelium remains a lethal and deforming disease due to tumour invasion, oro-facial destruction, cervical lymph node metastasis and ultimate blood-borne dissemination. Worldwide, 300 000 new cases are seen each year, with a recent and significant rise in incidence affecting particularly the young. To rationalize perspectives on preventive strategies in oral cancer management, this study addresses a number of fundamental questions regarding carcinogenesis: proliferation-what epithelial cell changes precede tumour development? Position-why are certain oral sites so predisposed to cancer? Progression-why do some precursor lesions progress to invasive carcinoma and others do not? Prediction-how can we predict individual patient and/or lesion behaviour to prevent disease progression? By improving our understanding of oral carcinogenesis, can we thereby facilitate more effective primary, secondary and tertiary preventive strategies and ultimately reduce the global burden of oral squamous cell carcinoma (OSCC)?

Increasing incidence of oral cancer in Hong Kong—Who, where…and why?

“…Whilst the overall burden of oral cancer in Hong Kong may not be numerically great, compared with more common cancers such as colorectal or lung (5437 and 4936 cases, respectively, registered during 2016 for example), the implications for the affected individual can be catastrophic: 57% of our study population died. Whilst the specific cause of death was not always evident in the CDARS database, this alarming statistic is consistent with previously raised concerns regarding the high mortality of established, invasive oral SCC …”

“…Invasive oral SCC results from multi‐factorial influences operating over prolonged periods, especially excessive consumption of tobacco products, alcohol misuse and betel quid habits, which act as external carcinogens targeting susceptible oral mucosal sites such as tongue, buccal mucosa and floor of mouth. It is recognised that genetic pre‐disposition and exogenous influences vary significantly between populations and, whilst tobacco smoking, alcohol consumption and increased age are probably the principal risk factors in Hong Kong (betel chewing being exceedingly rare), other as yet unknown factors may be equally relevant such as diet and nutrition, socio‐economic status and employment …”

“…As screening every individual is impractical, and very unlikely to improve overall outcome, a more pragmatic approach is to stratify risk in a patient population and to specifically identify and then target those groups deemed to be at greatest risk of cancer development . The particular relevance of patient profiling in oral oncology is the realisation that multiple tiers of preventive intervention are available and may be marshalled early in an attempt to minimise both the morbidity and high mortality resulting from established oral SCC …”

The“Newcastle Nomogram”—Statistical modelling predicts malignant transformation in potentially malignant disorders

“…Longitudinal patient cohort studies have provided substantive data to improve our understanding of PMD natural history . Whilst we have learned much, our ability to predict clinical outcome, especially MT, remains limited . Although based upon a Northern England population, the clinico‐pathological data from 590 newly presenting patients in this study provided an invaluable resource to populate our statistical model; salient features of age, gender, lesion, site and histopathology are all consistent with those reported globally for PMD .…”

“…Evolution of predictive statistical tools offers new opportunities to refine preventive and interventional strategies . Nomograms are graphical calculators that allow clinicians with limited statistical acumen to assess pre‐prepared two‐dimensional diagrammatical figures to calculate outcome predictions based upon risk factor analysis.…”