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nOralcancerposesacontinuingchal- lenge for dental practitioners world- wide. today international recently had the opportunity to speak with oral cancer expert Prof. Newell Johnson from Griffith University’s School of Dentistry and Oral Health in South- port, Australia, about the disease and new methods of identification and treatment. today international: Oral cancer figuresseemtobeincreasingworld- wide, despite awareness campaigns run by dental organisations. Are we indangeroflosingthebattleagainst the disease? Prof. Newell Johnson: There is some good news. In countries that havelonghadthereputationofhaving very high rates of oral cancer, such as parts of France, India and Sri Lanka, the rates of alcohol and tobacco- related oral cancer are indeed falling. The same is true of the US, much of Western Europe, and Australia. Here rates are falling from a lower base. In those countries or populations with traditionally very high rates, however, hundreds of thousands still die of oral cancer every year. In parts of Eastern Europe and the former Sovietrepublics,ratesofthesecancers are rising, we think, because of still hightobaccouse,abuseofalcoholand a poor diet. The other piece of bad news is that the incidence of cancers of the oropharynx (as opposed to the lip and in the mouth itself) is also increasing worldwide. HPV has been identified as a growing risk factor for oral cancer. Whatpartdoesthesexualtransmis- sionofthevirusplayinthedevelop- ment of the disease compared with more commonly known factors like smoking or drinking? Certain types of the human papil- lomavirus are indeed strongly asso- ciated with cancers of the upper aero- digestive tract, particularly of the ton- silsandbaseofthetongue,ratherthan inthemouthitself.Thesearethesame viruses that we know cause cancers of the uterine cervix, penis and anus. It is generally thought that sexual transmission is involved. The evi- denceislargelycircumstantial;thatis, these cancers are more likely among younger adults, and there are associa- tions with the number of sexual part- ners. Fortunately—if that is an appro- priate word—these cancers are more sensitive to radiotherapy, and the sur- vival rates/treatment outcomes are better than for most other head and neck cancers. For the past decade, there have been extensive immunisation pro- grammes against these particular pa- pillomaviruses delivered to girls in many countries. These are intended topreventcanceroftheuterinecervix in later life. It will be very interesting to observe, in another 20 years or so, whether this has had an impact on upperaero-digestivetractcancerstoo. Fortunately, we are beginning to see boys now included in the immunisa- tion programmes in some countries. Some forms of oral cancer have apatientsurvivalrateofonly50per cent. What makes it so difficult to achieve a more successful thera- peutic outcome? The average survival at five years after diagnosis of oral cancer has hovered around 40 to 50 per cent for decadesinmostcountries.Inthehigh- volumespecialisedtreatmentcentres, patients are indeed doing better, in terms of long-term survival and qual- ity of life/minimisation of disability and side-effects. The major reasons that we are not doing even better is because so manycasesarediagnosedandtreated so late, and/or patients have severe co-morbidities such as diseases of the cardiovascular system or cancers at other sites. Dentists can play a vital role in the identification of early signs of oral cancer. Is the profession suffi- ciently prepared for this role? Well, of course one cannot gener- alise. Many dentists and other mem- bers of the oral health team carry out excellent surveillance of each pa- tient. This is indeed our duty. It might be called “opportunistic screening”. Many national dental associations, and the FDI World Dental Federation, vigorously promote such behaviour. Therearemanyexcellenttrainingpro- grammes for the detection of patients and lesions at risk. This should go hand in hand with support from den- tists for tobacco prevention/cessation, moderation of alcohol consumption, promotion of healthy diets and good hygiene (oral and sexual) for all their clients. Ontheotherhand,theprevalence of potentially malignant disorders, and certainly of overt oral cancer, is lowinmanycountries,somaintaining a high level of awareness and interest among general practitioners is diffi- cult. Some are discouraged because cancer screening may not be a remu- nerable activity. In South Asia, and emigrant com- munitiestherefrom,potentiallymalig- nant oral disorders are common, and we have much activity with the pro- fessions and the public in these parts of the world. Recently, a study pub- lished in the Cancer Research journal has proposed a method of treatment by blocking a protein that plays an im- portant part in the spread and return of oral cancer. What are your views on this re- searchandwhatareotherpromising therapeutic approaches? There are very many biochemi- cal/molecular pathways involved in cell division, maturation, migration and metastasis, and death within tis- sues.Manyaretargetsofinvestigation and manipulation. Some will prove irrelevant—or at best epiphenomena. Interferencewithsomewillalsoaffect normal tissues, especially if they rep- resent exaggeration of pathways that are part of normal cellular controls. An attraction of this particular work is that it seeks to understand pathways critical to stem cells—those cells that provide the basis for con- tinued cell renewal. At the moment, the observations on this pathway in humancancershavebeenexploredin experimental animals. It is some way from human treatment trials, though therearemanyhumanstudiesofother putative biological treatments for oral and other cancers. In principle, this is the way forward. There are a number of oral can- cer-screening systems available on the market but their penetration is still very low. Why is this technol- ogy not yet part of dental practice? For cancers, and for potentially malignant disorders, in the mouth itself, direct visual inspection and palpation,followedbyreferralorbiop- sy, is the best approach. Adjunctive screening tests have not been demon- strated to have utility beyond this and commercialisation can be coun- terproductive. You have already mentioned genetics. What role will it play in the evaluation of oral cancer in the future? Well cancer is, of course, a genetic disease. There is a small component of inherited genetic susceptibility, but nothing as important as with breast cancer, for example. There is a large component of acquired genetic ab- normality, which is being gradually unravelled. So genetic testing is of in- creasing importance, perhaps for sus- ceptibility, more so for early changes in the tissue during carcinogenesis, the latter perhaps detectable in saliva or blood too. However,everycancerisaunique biological event in an unique individ- ual. Detecting the spectrum of genetic abnormalities in the individual pa- tient, and targeting these with partic- ular designer drugs, or gene therapy or immunotherapy is exciting: we are in the era of personalised medicine. Extensive surgery, radiotherapy and chemotherapy have not brought the improvedoutcomeswesodesperately need. For the afflicted, the future will be individualised biotherapies. For the world, the future must be primary prevention. Thank you very much for this interview. 7 science & practice22 Show Preview IDS Cologne 2013 www.idem-singapore.com THE BUSINESS OF DENTISTRY International Ms. Stephanie Sim T: +65 6500 6723 F: +65 6296 2771 E: s.sim@koelnmesse.com.sg Co-organizerSupported By Held InEndorsed By In Cooperation With The Gateway to the Asia Pacific’s Dental Markets IDEM Singapore is a highly targeted trade exhibition and conference that offers exhibitors unrivalled prospects to meet and do business with the dental fraternity in the Asia Pacific region. With almost 450 exhibitors participating from around the globe, IDEM Singapore 2014 will provide a truly international showcase of the trends shaping the world of dentistry. Capitalize on this unique opportunity and participate in this “must attend” event for every professional who is in the business of dentistry. INTERNATIONAL DENTAL EXHIBITION AND MEETING APRIL 4 - 6, 2014 Singapore Dental Association Visit the IDEM Singapore booth at We are located at Passage 10/11 Aisle No.V006 (Infocenter) AD “The surveillance of patients is each and every dentist’s duty” An interview with Prof.Newell Johnson,Australia 5 Prof. Newell Johnson