KEYNOTE ADDRESSES

Keynote Address I

Oral Candid a in health and disease Lakshman Samaranayake

Hon DSc, DDS (Glas), FRCPath, FDSRCS (Edin; ad hominem), FHKCPat h,FHKCDS King James IV Professo rship Oration 2011–2012, Royal College of Surgeons of Edinburgh , UK

As about one half of the human population harbour Candida spe- cies, the demystification of their conversio n from commen salism toparasitism causing mucosal and systemic candidiasi s would be ofconsiderabl e value in the management of these ailments, especially in compromi sed population groups. Human candidiasi s ranges from superficial infection s of the oral and vaginal mucosae , to life threat- ening multi-organ systemic affections. My presentati on describes how I attempted, over a period of three decades, to unveil the path- ogenic mechan isms of an enemy that ‘sleeps with us‘ ordinarily, yet strikes with a vengeance given the opportuni ty. In brief, the data presented is a thumb sketch of various novel discoveries on the clin- ical epidemiol ogy, aetiopat hogenesis, and clinical manage ment oforal candidal infection s.

Clinical epidemiol ogical findings from various cohorts includin gdiabetics, those on cytotoxic therapy, comatose patients, stroke suf- ferers, and from healthy individual s in three continent s indicated that the previous data on oral candida l carriage rates in healthy humans of 40–60% derived essentially from the West cannot beextrapola ted into Asia. Our findings indicate the prevalenc e rates are relativel y low in healthy Asians ranging from 14% to 40%.

With regard to aetiopath ogenesis, candida l biofilm life style isnow considered a crucial determ ining factor. A multitud e of studies we conducted illustrate (i) how dietary carbohy drates modulate bio- films, and its clinical implicatio ns on the genesis of oral candidiasis ,(ii) the conflicting role of whole saliva, serum, and sub-ther apeutic concentrati ons of antifungals on yeast biofilms, (iii) the finding that the drug resistance of candida l biofilms is due to their intrinsic anti- oxidative capacities , and (iv) the role of indigenou s oral bacteria inboth inhibit ing and fostering yeast biofilm developmen t.

With the advent of the HIV epidem ic novel variants of oral candidiasi s were described , throwing into disarray the conventiona ldisease classification. Hence a new improved classification, that has now received worldwid e acceptance was propos ed, where the dis- ease entities are principally categorised as primary and secondary oral candidiasi s, with further new sub-divisi ons thereafter.

An extensive enquiry into the oral manifestati ons of Asian and African cohorts with HIV disease highlight s salivary defences and secondary oral diseases that may differ from Western populations.Other novel findings relevant to HIV infecti on that will be discussed include, (i) the identification of global sub-type s of oral Candida

albicans , (ii) the ultrastru cture of pseudomem branous candidiasi s(iii) increased Sap expressi on in C. albicans and, (iv) the enhanced avidity of Candida to buccal epithelium of HIV carriers. Manageme ntof the clinical variants of oral candidiasi s poses new challenges and epidem iological survey s amongst both the young and the elderly indiffering geograph ic locales indicate the relativel y high, yet poorly manage d disease. For instance, the dual, candidal-stap hylococc alaetiology of angular cheilitis - an oft-ignored, peri-oral variant ofcandidiasi s.

In conclusion, this presentatio n redefines the clinical epidemiol- ogy, and the complex behavioural patterns of Candida species within the human oral habitat, that may lead to a deeper understand ing ofthe preventi on and management of mucosal candidal infection s ingeneral, and oral candidiasis , specifically.

doi:10.1016/j.oraloncology.20 13.03.461

Keynote Address II

Oral cancer; impacting disease load, awareness and diagnosis Crispian Scully

UCL, UK

Oral cancer is a significant challenge, with around 300,000 new cases identified worldwid e each year. Oral cancer aetiology is still largely a disease of older age and due to lifestyle risk factors, notably tobacco, alcohol and betel and thus potentially preventa ble, with increasing incrimination of HPV in some tumours and younger ages.Environm ental and genetic factors appear less important , and in any event are difficult to address.

The past decades have seen a number of public awareness and screenin g campaign s in several countries, and improvem ents inmanage ment outcome. But have we impacted disease load,awarene ss or diagnosis, and initiated treatment earlier and more effective ly?

Worryingl y, the mortalit y and morbidity rates remain high,largely because of late diagnosis. Currently there is insufficientevidence to support or refute the use of visual examination as ascreenin g method for oral cancer in the general population inresource -rich areas. There is limited evidence that screening could be cost-effectiv e (Brocklehurst P et al. Screening programme s for the early detection and prevention of cancer. Cochrane Database Syst Rev 2010;11:CD0 04150) but not at the level suggested in the assumpti ons from the Indian study (Sankaranarayanan R et al.Trivandru m Oral Cancer Screening Study Group. Effect of screening on oral cancer mortality in Kerala, India: a cluster-ran domised controll ed trial. Lancet 2005;365:1927–33).

Oral Oncology 49 (2013) S1–S3

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Oral Oncolog y

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