Hepatitis Viruses Etiology, epidemiology, pathogenesis, classification.
EPIDEMIOLOGY, ETIOLOGY AND PREVENTION OF ORAL CANCER
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Transcript of 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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