EPIDEMIOLOGY, ETIOLOGY AND PREVENTION OF ORAL CANCER - PowerPoint Presentation

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EPIDEMIOLOGY, ETIOLOGY AND PREVENTION OF ORAL CANCER

Sheethal M. SherifIII rd YR BDS

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CANCER

A “neoplasm” is defined as an abnormal mass of tissue, the growth of which exceeds and is uncoordinated with the normal tissues and persists in the same excessive manner even after cessation of the stimuli which evoked the change Any malignant tumour 4 characteristic features: Clonality Autonomy Anaplasia Metastasis

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Contd…

Oncogenes: cause malignant transformation Suppressor genes: induce programmed cell death; when lost/inactivated  tumorgenesis

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Mutation

Amplification

Re arrangements

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ORAL CANCER

One of the ten leading cancers in the worldAny malignancy that arises from oral tissues90-95% Squamous cell carcinomaAnnually 7% of all cancer death in males 4% of all cancer death in females

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Oral precancer

WHO Definition: Morphologically altered tissue in which cancer is more likely to develop than in its apparently normal counterpart E.g.: Leukoplakia, Erythroplakia, Palatal changes associated with reverse smokingIntermediate clinical state with increased cancer risk, which can be recognized and treated, obviously with a much better prognosis than a full-blown malignancy

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Prevalence and incidence

Max. prevalence- 5th to 6th decades of life because: prolonged duration of exposure to initiators and promoters of cancer cellular aging decreased immunological responseIn highly industrialised countries-3-5% In developing countries-40%

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Contd……

About 2.5 lak new cases occur every year in India, Pakistan, Bangladesh etcStudy done in Mumbai, Pune, Chennai and Bangalore: Higher in males except in BangaloreIndian Oral Cancer – Buccal mucosa(65%), lower alveolus(30%) and retromolar trigone(5%) : as these constitute more than 60% of all cancers

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Etiology of oral cancers

TobaccoOther tobacco lime preparationsOther forms of powdered tobaccoSmoking

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tobacco

According to WHO(1984)---90%---directly attributable to chewing and tobacco smokingHISTORYTobago/TobaccaHookahDental Snuff—relieve tooth ache, bleeding gums, preserve and whiten teeth, prevent decayIn India, 70%- beedi; 10%- cigarettes; 20%- smokeless tobacco

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TOBACCO PREPARATION Tobacco leaves curing (fire curing, sun curing) for partial drying further dryingfermentation/sweetening for months upto 2 years

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TOBACCO PREPARATIONS PREVALENT IN INDIABeedi: -most popular -1.7-3 mg nicotine; 40-50 mg tarChillum: -held vertically—pebble introduced—tobacco glowing charcoalChutta: -cured tobacco wrapped in dry tobacco leafCigarettes: -1-1.4 mg nicotine; 19-27 mg tar -more common in urban areas

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Dhumti: -rolled leaf tobacco inside leaf of jack fruit tree/dried leaf of banana plant -for reverse smoking among womenGudakhu: -paste of powdered tobacco, molasses and other ingredients (to clean the tooth) -used among women in BiharHookah: -also called water pipe/hubble bubble -In places with strong Mughal cultural influence

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Hookli: -Clay pipe with mouth piece and bowl -In Bhavnagar district of GujaratKhaini: -Powdered sun-dried tobacco, slaked lime[Ca(OH)2] paste mixture used with arecanut -Placed in mouth/chewedMainpuri tobacco: -tobacco, slaked lime, finely cut arecanut, camphor & clovesMawa: -thin shavings of arecanut, tobacco, slaked lime

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Mishri/Masheri: -roasting tobacco(on hot metal plate)until uniformly black  powdered  with/without catechuPaan: -betel leaf & quid contains arecanut -also aniseed, catechu, cardamom, cinnamon, coconut, cloves, sugar and tobaccoSnuff: -finely powdered air-cured and fire-cured tobacco leaves -dry/moist, used plain/with ingredients, orally/nasallyZarda: -tobacco leaf boiled with lime & spices until evaporation  residue dried coloured with dye  chewed

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Constituents of tobacco

CONSTITUENTSADVERSE EFFECTSPolycyclic aromatic hydrocarbonCarcinogenesisNicotineCarcinogenicPhenolGanglionic stimulation and depression & tumour promotionBenzopyreneTumour promotion & irritationCOImpaired O2 transport and repairFormaldehyde and oxides of N2Toxicity to cilia and irritationNitrosamineCarcinogenic

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Classification of lesions in the oral cavity

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Benign tumors of epithelial tissue origin

PapillomaSquamous AcanthomaPigmented Cellular Nevus

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Premalignant lesions of epithelial origin

LeukoplakiaLeukodemaErythroplakiaIntraepithelial Carcinoma

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Malignant tumors of epithelial tissue origin

Basal cell carcinomaSquamous cell carcinomaCarcinoma of lip, tongue, floor of the mouth, gingiva, buccal mucosa, palate & maxillary sinusVerrucous carcinomaAdenoid squamous cell carcinomaMalignant melanoma

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Benign tumors of connective tissue origin

FibromaGiant cell fibromaPeripheral central ossifying granulomaLipomaHemangiomaMyxomaChondromaCodman’s tumor (Benign chondroblastoma)Osteomas

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Malignant tumors of connective tissue origin

FibrosarcomaLiposarcomaKaposis sarcomaEwings sarcomaChondro/Osteo sarcomaNon- Hodgkins lymphomaBurkitts lymphoma (African Jaw lymphoma)Multiple myeloma

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leukoplakia

A raised white part of the oral mucosa measuring 5mm or more which cannot be scraped off and which cannot be attributed to any other diagnosable diseases.Most common Pre cancerous lesionAge- 35 to 54 yrs

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ETIOLOGYSmokingSpiritsSpicesSepsisSharp tooth edgeSyphilisTobacco chewingVitamin deficiencyEndocrine disturbancesGalvanismActinic radiationBlood group AViral agents

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CLINICAL TYPES OF LEUKOPLAKIAHomogenous leukoplakia: -raised plaque formation consisting of a plaque or groups of plaque varying in size with irregular edges

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Ulcerated leukoplakia: -a red area which at times exhibits yellowish areas of fibrin -may appear as a small red area with or without pigmentation on the periphery -narrow rectangular ulceration consisting of a few whitish areas

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Nodular leukoplakia: -small white specks or nodules on an erythematous base -very fine pin head size or even larger

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MALIGNANT TRANSFORMATION OF LEUKOPLAKIAWhen a lesion develops cracks, bleeding or areas of redness and erosion------>malignant transformation 3-6%---malignant over 10 yr periodHighest risk---lesions over 1 cmNodular lesions have highest risk of malignant transformation

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Oral submucous fibrosis

It is a precancerous conditionDefined as a chronic mucosal condition affecting any part of the oral mucosa characterised by mucosal rigidity of varying intensity due to fibroelastic transformation of the juxta epithelial connective tissue layerMax. incidence- 30-50 yrsFemale predelictionMost common presenting symptom- inability to fully open the mouthIncrease in cashew workers in Kerala

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etiology

Betel nut chewingNutritional deficiencyGenetic susceptibilityAutoimmunityCollagen disordersBlood group A

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Clinical features

Presence of palpable fibrous bands in the buccal mucosa, retromolar areas and rima orisInitial symptoms:Burning sensation of oral mucosaBlanching of oral mucosaTongue becomes devoid of papillaeLater symptoms:Opening of mouth is restrictedPt cannot protrude tongue beyond the incisal edges

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erythroplakia

Any area of reddened velvety-texture mucosa that cannot be identified on the basis of clinical and histopathologic examination as being caused by inflammation or any other disease processRare but severe precancerous lesionTo distinguish from benign inflammatory lesions : 1% toluidine blue solution applied topically with a swab/oral rinse

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TYPES OF ERYTHROPLAKIAHomogenous erythroplakiaGranular erythroplakia

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MALIGNANT TRANSFORMATION OF ERYTHROPLAKIAHigher potential of malignant transformationMicroscopically, 91% show squamous cell carcinoma

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Squamous cell carcinoma (epidermoid carcinoma)

Most malignant neoplasm in the oral cavityCan occur as:Carcinoma of lipCarcinoma of tongueCarcinoma of floor of mouthCarcinoma of buccal mucosaCarcinoma of gingivaCarcinoma of palateCarcinoma of maxillary sinus

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Carcinoma of lip

ETIOLOGYUse of tobacco through pipe smokingSyphilisSunlightPoor oral hygieneleukoplakia

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CLINICAL FEATURESDepends on duration of lesion and nature of growthStarts at vermillion border and progresses to one side of midlineCommences as small area of induration and ulceration---increase in size---crater like defectSlow to metastasizeBefore evidence of regional lymphnode involvement--->massive lesion

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Carcinoma of tongue

Most frequent location after buccal mucosaMost important etiology: beedi smoking

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CLINICAL FEATURESEarly lesions - pain and sore throatUpto 80% - anterior 2/3rd ;more frequently on its lateral margins and the ventral surfaceEarly lesions may appear like a leukoplakia or as a red area interspersed with nodulesRare in the dorsum and the tip

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Carcinoma of floor of mouth

ETIOLOGYSmoking especially pipes or cigarsConsumption of alcoholPoor oral hygieneleukoplakia

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CLINICAL FEATURESInitially, reddish area or thickened mucosa---indurated ulcer situated on one side of the midlineMay or may not be painfulMore frequent in anterior portionPt complains of difficulty in speech , excessive salivation or referred pain in earMay invade to deeper tissues ( submaxillary and sublingual gland)Contralateral metastasis are often present

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Carcinoma of buccal mucosa

ETIOLOGYChewing tobacco and retaining the quid in the buccal vestibule for several yearsLeukoplakiaChronic trauma and irritation by a sharp tooth

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CLINICAL FEATURESPainful ulcerative lesion with induration and infiltration into deeper tissuesDevelops along the line opposite the plane of occlusion or inferior to itMay appear superficial and grow outwardMetastasis is high

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Carcinoma of gingiva

ETIOLOGYChronic inflammation and irritation due to calculus formation and collection of micro organismsHave been reported after extraction of tooth

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CLINICAL FEATURESMore frequent in maxilla than mandibleInitially an area of ulceration is seenMay or may not be painfulArises more commonly in edentulous areasMore common in attached gingivaMaxillary gingival carcinoma often invades into maxillary sinusMandibular gingival carcinoma infiltrates into floor of mouth/cheek/boneIn advanced stage, it may progress to pathologic fractureMetastasis is common

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Carcinoma of palate

Uncommon locationUsually seen in reverse smokers

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CLINICAL FEATURESPoorly defined, painful ulcerated lesion either in the centre or on the glandular zone of hard palateExophytic and broad basedFrequently crosses the midline, may extend to lingual gingiva and tonsillar pillarIn advanced stages, may invade into bone or nasal cavity

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Carcinoma of maxillary sinus

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Kaposi’s sarcoma

Indolent tumour with slowly progress growthMost affected site in oral cavity - hard palateDiagnostic sign for AIDSMultifocal with numerous isolated and coalescing plaquesIncrease in size---nodular---involve entire palate---protrude below the plane of occlusionMore hemosiderin---more brown

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Prevention and control of oral cancer

65-80% attributable to lifestyle3 well-known approaches:Regulatory or legal approachService approachEducational approach

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Regulatory approach

In India, Cigarette act 1975 – print warnings on cigarette packetsNational Cancer Control Programme, 1985 – health warning displays & banning of advertisements on tobacco productsIn countries like Italy, Norway, Portugal etc – ban on advertising tobacco products

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Service approach

Active search for a disease is important for prevention---screeningIn order to be suitable for screening:Disease is serious, yet treatable in early stagesTreatment is usually acceptable to asymptomatic pts and provides better benefit over later treatmentFacilities for diagnosis and treatment existsNatural history of disease is knownScreening tool is inexpensive and safe

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Contd…

Other than professionals, primary health care workers can also do the screeningDentists play an important role in early detection of oral cancersAlso many are missed because early oral cancers have an extremely variable clinical appearance

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Educational approach

People should be encouraged to give up harmful habitsIndividual with clinical symptoms should be kept under careful observationEffective facilities for early diagnosis and treatmentLocal methods used for prevention should be applied only if they have been shown scientifically effective The public should be informed about:Consequences of oral cancerThe risk that oral precancer lesions may develop into oral cancerImportance of early diagnosis and treatment of oral mucosal lesions

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Exfoliative cytology

Quick, simple, painless and bloodless procedureIneffective with lesions that have heavy keratin layerReports:Class I: NormalClass II: Minor atypia with no malignant changesClass III: Wider atypia suggestive of cancerClass IV: Few cells with malignant characteristics. Biopsy is mandatoryClass V: Cells are malignant. Biopsy is mandatory

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Biopsy techniques

After adequate LA is obtained, silk suture is introduced--->small elliptical incision is created with a scalpel--->incisions are carried into underlying connective tissue and the specimen is removed on the suture---> tissue suspended over the specimen bottle and suture is cut allowing to fall into preservative solutionBiopsy forceps are preferred

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DISPOSABLE BIOPSY FORCEPS

NEEDLELESS BIOPSY FORCEPS

REUSABLE BIOPSY FORCEPS

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Toluidine blue vital staining

Toluidine blue dye is used as adjunct to biopsy1% solution of toluidine blue is used as mouthwash--->retained in the area of diffuse lesion for 1 min--->irrigated with 1% acetic acid--->stains malignant lesion blue

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Prevention of oral cancer

PREVENTIVE SERVICESHEALTH PROMOTIONSPECIFIC PROTECTIONEARLY DIAGNOSIS AND PROMPT TREATMENTSERVICES PROVIDED BY INDIVIDUALPeriodic visits to dental officeAvoidance of known irritantsSelf examination, Use of dental servicesSERVICES PROVIDED BY COMMUNITYDental health education programmes, Promotion of research Periodic screening, Provision of dental servicesSERVICED PROVIDED BY DENTAL PROFESSIONALPatient educationRemoval of known irritants in oral cavityExamination, biopsy, radiation therapy, oral cytology, complete excision

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Staging of cancer

The International Union Against Cancer (UICC 1987) evolved the criteria for a staging classification scheme for cancer- TNM system T- Extent of the primary tumour N- The condition of regional lymphnodes M- Absence or presence of metastasisIn addition, two other parameters are also considered P- Pathology S- Site

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Stage grouping [American joint committee on cancer]

STAGE 0Carcinoma in situ;No lymphnode involvement(N0) or metastasis(M0)STAGE ITumour less than 2 cm(T1) N0 M0 STAGE IITumour more than 2 cm but less than 4 cm(T2) N0 M0STAGE IIITumour more than 4 cm(T3) with N0 and M0T1 N1(involves single lymphnode <3cm) M0T2 N1 M0T3 N1 M0STAGE IVT1 N2(involves multiple lymphnodes >3cm <6cm) M0T1 N3(metastasis in a lymphnode >6 cm) M0T2 N2 M0T2 N3 M0T3 N2 M0T3 N3 M0Any T or N category with M1(distant metastasis)

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Treatment modalities

Most patients with squamous cell carcinoma of oral cavity, oropharynx and hypopharynx undergo surgery, radiation therapy or combined modality therapyChemotherapy is not the first line treatmentFor a given T stage, prognosis is best for tumours of lips and deteriorates as the site moves toward the hypopharynx

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Treatment for precancerous lesions

Homogenous leukoplakia: cessation of tobacco useNon Homogenous leukoplakia + candida infection: Antifungal treatment---->surgically excisedErythroplakia: surgically removedSMF: giving up tobacco chewing + systemic corticosteroids + local hydrocortisone

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Treatment of cancer

High cure rates in Stage I and early Stage II by surgery and radiotherapy aloneStage III and IV fare poorly with any treatmentTreatment modalities:SurgeryRadiotherapyChemotherapy

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surgery

Curative surgery removal of a tumor when it appears to be confined to one areaCurative surgery is thought of as a primary treatment of the cancerused along with chemotherapy or radiation therapyDebulking (or cytoreductive) surgery is done in some cases when removing a tumor entirely would cause too much damage to an organ or surrounding areasthe doctor may remove as much of the tumor as possible and then try to treat what’s left with radiation therapy or chemotherapy

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Contd…

Palliative surgery is used to treat complications of advanced diseasenot intended to cure the cancerused to correct a problem that is causing discomfort or disability or painRestorative (or reconstructive) surgery is used to restore a person’s appearance or the function of an organ or body part after primary surgery.Eg:prosthetic (metal or plastic) materials after surgery for oral cavity cancers

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radiotherapy

Treatment of disease with X-rays or other radiationsTreatment dose is expressed in ‘rad’Dose depends on volume of tumourLess than 3% cancer occur from radiationMost sensitive to radiation- Bone marow, breast and thyroid4 techniques:External irradiationPerioral irradiationInterstitial irradiationSurface irradiation

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chemotherapy

Affects malignant cells in one of the following ways:Damage the DNAInhibit DNA synthesisStop mitotic processes so that the cell cannot divide Drugs used are:Alkylating agents – Mechlorathamine, Busulfan Vinca alkaloids – Vincristine, VinblastineAntibiotics – DoxorubicinTaxanes – DocetaxelAnti-metabolites – 6 Mercaptopurine, 5 FU

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Newer treatment modalities in oral cancer

ImmunotherapyImmune substances are produced in the lab for use in cancer treatment – Biological Response ModifiersBRMs alter the interaction between the body’s immune defenses and cancer cells to boost, direct, or restore the body’s ability to fight the diseaseGene therapy a gene may be inserted into an immune system cell to enhance its ability to recognize and attack cancer cellsscientists inject cancer cells with genes that cause the cancer cells to produce cytokines and stimulate the immune systemCancer vaccines – under study

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Treatment complication

Radiation cariesPeriodontal issuesAltered oral floraStomatitisOsteoradionecrosisXerostomiaCandida infectionMucositisDysguisia

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Supportive services and rehabilitation

Maintenance of nutrition – orally/tube-feedingOral hygiene and dental careUse of vitamins, proteins, antibiotics & mouthwashesRehabilitation depends on extent of surgical excisionShould be done by a team of speech and occupational therapists, physiotherapists, medicosocial worker, maxillofacial prosthodontist and psychiatristRelief of pain – in inoperable and very advanced cases

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De-addiction programme for smokers

In Oct 1996, Ciba-Geigy introduced the first transdermal patch to wean smokers away from the habit in India90 day programme – Rs.9000Proper counselling is important

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conclusion

“No Tobacco Day” is being observed on the 31st MayThe suffering, disfigurement and death due to oral cancer is easily avoidable since the factors associated with the disease have been identified. Another important aspect is its easy accessibility for diagnosis. This feature along with the finding that oral cancer is generally preceded by precancerous lesions provide an excellent opportunity for early detection and control.

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