EPIDEMIOLOGY, ETIOLOGY AND PREVENTION OF ORAL CANCER

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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:

ClonalityAutonomyAnaplasiaMetastasis

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CONTD… Oncogenes: cause malignant

transformation

Suppressor genes: induce programmed cell death; when lost/inactivated tumorgenesis

Mutation

Amplification

Re arrangements

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ORAL CANCER

One of the ten leading cancers in the world

Any malignancy that arises from oral tissues

90-95% Squamous cell carcinoma Annually

7% of all cancer death in males4% 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 counterpartE.g.: Leukoplakia, Erythroplakia, Palatal changes associated with reverse smoking

Intermediate 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 cancercellular agingdecreased immunological

response In 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 etc Study done in Mumbai, Pune, Chennai

and Bangalore: Higher in males except in Bangalore

Indian 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 CANCERS1. Tobacco2. Other tobacco lime preparations3. Other forms of powdered tobacco4. Smoking

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TOBACCO According to WHO(1984)---90%---directly

attributable to chewing and tobacco smoking

HISTORY Tobago/Tobacca Hookah Dental Snuff—relieve tooth ache, bleeding

gums, preserve and whiten teeth, prevent decay

In India, 70%- beedi; 10%- cigarettes; 20%- smokeless tobacco

Y

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TOBACCO PREPARATION

Tobacco leaves

curing (fire curing, sun curing) for partial drying

further drying

fermentation/sweetening for months upto 2 years

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TOBACCO PREPARATIONS PREVALENT IN INDIA

Beedi:-most popular-1.7-3 mg nicotine; 40-50 mg tar

Chillum:-held vertically—pebble introduced—tobacco glowing charcoal

Chutta:-cured tobacco wrapped in dry tobacco leaf

Cigarettes:-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

women Gudakhu:

-paste of powdered tobacco, molasses and other ingredients (to clean the tooth)

-used among women in Bihar Hookah:

-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 Gujarat

Khaini:-Powdered sun-dried tobacco, slaked lime[Ca(OH)2] paste mixture used with arecanut-Placed in mouth/chewed

Mainpuri tobacco:-tobacco, slaked lime, finely cut arecanut, camphor & cloves

Mawa:-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 catechu

Paan:-betel leaf & quid contains arecanut-also aniseed, catechu, cardamom, cinnamon, coconut, cloves, sugar and tobacco

Snuff:-finely powdered air-cured and fire-cured tobacco leaves-dry/moist, used plain/with ingredients, orally/nasally

Zarda:-tobacco leaf boiled with lime & spices until evaporation residue dried coloured with dye chewed

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CONSTITUENTS OF TOBACCO

CONSTITUENTS ADVERSE EFFECTS

Polycyclic aromatic hydrocarbon

Carcinogenesis

Nicotine Carcinogenic

Phenol Ganglionic stimulation and depression & tumour promotion

Benzopyrene Tumour promotion & irritation

CO Impaired O2 transport and repair

Formaldehyde and oxides of N2 Toxicity to cilia and irritation

Nitrosamine Carcinogenic

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CLASSIFICATION OF LESIONS IN THE ORAL CAVITY

Benign tumours of epithelial

origin

Premalignant lesions of

epithelial origin

Malignant tumours of

epithelial tissue origin

Benign tumours of connective tissue origin

Malignant tumours of

connective tissue origin

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BENIGN TUMORS OF EPITHELIAL TISSUE ORIGIN Papilloma

Squamous Acanthoma Pigmented Cellular Nevus

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PREMALIGNANT LESIONS OF EPITHELIAL ORIGIN

Leukoplakia

Leukodema Erythroplakia

Intraepithelial Carcinoma

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MALIGNANT TUMORS OF EPITHELIAL TISSUE ORIGIN Basal cell carcinoma Squamous cell carcinoma Carcinoma of lip, tongue, floor of the

mouth, gingiva, buccal mucosa, palate & maxillary sinus

Verrucous carcinoma Adenoid squamous cell carcinoma Malignant melanoma

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BENIGN TUMORS OF CONNECTIVE TISSUE ORIGIN Fibroma Giant cell fibroma Peripheral central ossifying granuloma Lipoma Hemangioma Myxoma Chondroma Codman’s tumor (Benign

chondroblastoma) Osteomas

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MALIGNANT TUMORS OF CONNECTIVE TISSUE ORIGIN Fibrosarcoma Liposarcoma Kaposis sarcoma Ewings sarcoma Chondro/Osteo sarcoma Non- Hodgkins lymphoma Burkitts 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 lesion Age- 35 to 54 yrs

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ETIOLOGY Smoking Spirits Spices Sepsis Sharp tooth edge Syphilis Tobacco chewing Vitamin deficiency Endocrine disturbances Galvanism Actinic radiation Blood group A Viral agents

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CLINICAL TYPES OF LEUKOPLAKIA

Homogenous 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 LEUKOPLAKIA

When a lesion develops cracks, bleeding or areas of redness and erosion------>malignant transformation

3-6%---malignant over 10 yr period Highest risk---lesions over 1 cm Nodular lesions have highest risk of

malignant transformation

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ORAL SUBMUCOUS FIBROSIS

It is a precancerous condition Defined 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 layer

Max. incidence- 30-50 yrs Female predeliction Most common presenting symptom-

inability to fully open the mouth Increase in cashew workers in Kerala

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ETIOLOGY Betel nut chewing Nutritional deficiency Genetic susceptibility Autoimmunity Collagen disorders Blood group A

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CLINICAL FEATURES Presence of palpable fibrous bands in

the buccal mucosa, retromolar areas and rima oris

Initial symptoms:Burning sensation of oral mucosaBlanching of oral mucosaTongue becomes devoid of papillae

Later 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 process

Rare but severe precancerous lesion To distinguish from benign inflammatory

lesions : 1% toluidine blue solution applied topically with a swab/oral rinse

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TYPES OF ERYTHROPLAKIA

Homogenous erythroplakia

Granular erythroplakia

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MALIGNANT TRANSFORMATION OF ERYTHROPLAKIA

Higher potential of malignant transformation Microscopically, 91% show squamous cell

carcinoma

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SQUAMOUS CELL CARCINOMA (EPIDERMOID CARCINOMA)

Most malignant neoplasm in the oral cavity

Can 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 LIPETIOLOGY Use of tobacco through pipe smoking Syphilis Sunlight Poor oral hygiene leukoplakia

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CLINICAL FEATURES

Depends on duration of lesion and nature of growth

Starts at vermillion border and progresses to one side of midline

Commences as small area of induration and ulceration---increase in size---crater like defect

Slow to metastasize Before evidence of regional lymphnode

involvement--->massive lesion

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CARCINOMA OF TONGUE Most frequent location after buccal

mucosa Most important etiology: beedi smoking

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CLINICAL FEATURES

Early lesions - pain and sore throat Upto 80% - anterior 2/3rd ;more

frequently on its lateral margins and the ventral surface

Early lesions may appear like a leukoplakia or as a red area interspersed with nodules

Rare in the dorsum and the tip

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CARCINOMA OF FLOOR OF MOUTH

ETIOLOGY Smoking especially pipes or cigars Consumption of alcohol Poor oral hygiene leukoplakia

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CLINICAL FEATURES

Initially, reddish area or thickened mucosa---indurated ulcer situated on one side of the midline

May or may not be painful More frequent in anterior portion Pt complains of difficulty in speech ,

excessive salivation or referred pain in ear May invade to deeper tissues

( submaxillary and sublingual gland) Contralateral metastasis are often present

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CARCINOMA OF BUCCAL MUCOSAETIOLOGY Chewing tobacco and retaining the quid

in the buccal vestibule for several years Leukoplakia Chronic trauma and irritation by a sharp

tooth

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CLINICAL FEATURES Painful ulcerative lesion with induration

and infiltration into deeper tissues Develops along the line opposite the

plane of occlusion or inferior to it May appear superficial and grow

outward Metastasis is high

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CARCINOMA OF GINGIVAETIOLOGY Chronic inflammation and irritation due

to calculus formation and collection of micro organisms

Have been reported after extraction of tooth

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CLINICAL FEATURES

More frequent in maxilla than mandible Initially an area of ulceration is seen May or may not be painful Arises more commonly in edentulous areas More common in attached gingiva Maxillary gingival carcinoma often invades into

maxillary sinus Mandibular gingival carcinoma infiltrates into

floor of mouth/cheek/bone In advanced stage, it may progress to pathologic

fracture Metastasis is common

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CARCINOMA OF PALATE Uncommon location Usually seen in reverse smokers

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CLINICAL FEATURES

Poorly defined, painful ulcerated lesion either in the centre or on the glandular zone of hard palate

Exophytic and broad based Frequently crosses the midline, may

extend to lingual gingiva and tonsillar pillar

In 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

growth Most affected site in oral cavity - hard

palate Diagnostic sign for AIDS Multifocal with numerous isolated and

coalescing plaques Increase in size---nodular---involve entire

palate---protrude below the plane of occlusion

More hemosiderin---more brown

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PREVENTION AND CONTROL OF ORAL CANCER 65-80% attributable to lifestyle 3 well-known approaches:

Regulatory or legal approach

Service approach

Educational approach

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REGULATORY APPROACH

In India, Cigarette act 1975 – print warnings on cigarette packets

National Cancer Control Programme, 1985 – health warning displays & banning of advertisements on tobacco products

In 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---screening In order to be suitable for screening:

Disease is serious, yet treatable in early stages

Treatment is usually acceptable to asymptomatic pts and provides better benefit over later treatment

Facilities 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 screening Dentists play an important role in early

detection of oral cancers Also 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 habits Individual with clinical symptoms should be

kept under careful observation Effective facilities for early diagnosis and

treatment Local methods used for prevention should be

applied only if they have been shown scientifically effective

The public should be informed about: Consequences of oral cancer The risk that oral precancer lesions may develop

into oral cancer Importance of early diagnosis and treatment of

oral mucosal lesions

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EXFOLIATIVE CYTOLOGY Quick, simple, painless and bloodless

procedure Ineffective with lesions that have

heavy keratin layer Reports:

Class I: Normal Class II: Minor atypia with no malignant

changes Class III: Wider atypia suggestive of cancer Class IV: Few cells with malignant

characteristics. Biopsy is mandatory Class 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 solution

Biopsy 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 biopsy

1% 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 SERVICES

HEALTH PROMOTION

SPECIFIC PROTECTION

EARLY DIAGNOSIS AND PROMPT TREATMENT

SERVICES PROVIDED BY INDIVIDUAL

Periodic visits to dental office

Avoidance of known irritants

Self examination, Use of dental services

SERVICES PROVIDED BY COMMUNITY

Dental health education programmes, Promotion of research

Periodic screening, Provision of dental services

SERVICED PROVIDED BY DENTAL PROFESSIONAL

Patient education

Removal of known irritants in oral cavity

Examination, 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 tumourN- The condition of regional

lymphnodesM- Absence or presence of

metastasis In addition, two other parameters are

also consideredP- PathologyS- Site

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STAGE GROUPING [AMERICAN JOINT COMMITTEE ON CANCER]

STAGE 0 Carcinoma in situ;No lymphnode involvement(N0) or metastasis(M0)

STAGE I Tumour less than 2 cm(T1) N0 M0 STAGE II Tumour more than 2 cm but less than 4 cm(T2)

N0 M0STAGE III Tumour more than 4 cm(T3) with N0 and M0

T1 N1(involves single lymphnode <3cm) M0T2 N1 M0T3 N1 M0

STAGE IV T1 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 therapy

Chemotherapy is not the first line treatment

For 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 use

Non Homogenous leukoplakia + candida infection:Antifungal treatment---->surgically excised

Erythroplakia:surgically removed

SMF: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 alone

Stage III and IV fare poorly with any treatment

Treatment modalities:SurgeryRadiotherapyChemotherapy

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SURGERY Curative surgery

removal of a tumor when it appears to be confined to one area

Curative surgery is thought of as a primary treatment of the cancer

used along with chemotherapy or radiation therapy

Debulking (or cytoreductive) surgery is done in some cases when removing a tumor

entirely would cause too much damage to an organ or surrounding areas

the 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 disease

not intended to cure the cancerused to correct a problem that is causing

discomfort or disability or pain Restorative (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

radiations Treatment dose is expressed in ‘rad’ Dose depends on volume of tumour Less than 3% cancer occur from radiation Most sensitive to radiation- Bone marow,

breast and thyroid 4 techniques:

External irradiation Perioral irradiation Interstitial irradiation Surface irradiation

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CHEMOTHERAPY Affects malignant cells in one of the

following ways:Damage the DNA Inhibit 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 Immunotherapy

Immune substances are produced in the lab for use in cancer treatment – Biological Response Modifiers

BRMs alter the interaction between the body’s immune defenses and cancer cells to boost, direct, or restore the body’s ability to fight the disease

Gene therapy a gene may be inserted into an immune system cell

to enhance its ability to recognize and attack cancer cells

scientists inject cancer cells with genes that cause the cancer cells to produce cytokines and stimulate the immune system

Cancer vaccines – under study

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TREATMENT COMPLICATION

Radiation caries Periodontal issues Altered oral flora Stomatitis Osteoradionecrosis Xerostomia Candida infection Mucositis Dysguisia

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SUPPORTIVE SERVICES AND REHABILITATION

Maintenance of nutrition – orally/tube-feeding Oral hygiene and dental care Use of vitamins, proteins, antibiotics &

mouthwashes Rehabilitation depends on extent of surgical

excision Should be done by a team of speech and

occupational therapists, physiotherapists, medicosocial worker, maxillofacial prosthodontist and psychiatrist

Relief 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 India

90 day programme – Rs.9000 Proper counselling is important

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CONCLUSION “No Tobacco Day” is being observed on

the 31st May The 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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