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Articles

Clinical Tips Series - Oral Cancer

Recognizing the Oral White Lesion and Oral Cancer in Daily Clinical Routine
Dr How Kim Chuan 80S (Singapore) MSc Orthodontics (London) MORTH PCS (England) MORTH RCSEd (Edinburgh) FDS RCS (England) FDS RCSEd (Edinburgh) Cert Oral Implantology FICOI


Introduction

I was inspired to write this article after hearing the speech by the Director of Oral Health, Dato DrWan Mohd Nasir on 7 August 2004 at the Opening Ceremony of the 11th CPD Blockbuster Scientific Conference & Trade Exhibition. In his speech, Dato Dr Wan touched on smoking and its potential pre-cancerous effects. He encouraged the clinician to detect lesion early so that it could be treated with better prognosis. Incidentally, a few days after his speech, a patient came in my clinic and she was suffered from this suspicious lesion. Instantly the alarm was triggered and true enough the lesion was subsequently diagnosed as Squamous cell carcinoma after histological confirmation from the biopsy.


Etiology of Cancer and its Prevention

Cancer prevention is a diverse area that touches on subjects such as epidemiology, clinical medicine, screening, cancer biology, immunobiology, behavioral medicine, stress management and education. Cancer develops as a result of both endogenous, or host, and exogenous, or environmental factors. Endogenous factors and preconception, prenatal and postnatal exogenous factor may lead to childhood cancers; similarly, endogenous and exogenous factors interact in the natural history of adult cancers.

Genetic Identification

Identifying genes that put children and adult at risk is an important and labor-intensive task. Overall, probably few cancers are entirely due to germ line mutations. Genetic research will eventually help us identify patients who are at high risk to certain types of cancers.

Environmental Factors

Most human adult cancers are believed to be related to environmental exposures and of which many have been identified in a causal role. Chemical compounds associated with increased risk include arsenic, asbestos, bis (chlomethyl) ether and chloromethyl methyl ethr, chromium, nickel, polycyclic aromatic hydrocarbons, radon, and vinyl chloride. Environmental exposures associated with increased cancer risk include tobacco, alcohol, ionizing radiation, ultraviolet radiation, exogenous estrogen, Epstein-Barr virus (HBV), hepatitis B and C (HPB, HPC) and H, human immunodeficiency virus (HIV), human T lymph tropic virus, Helicobacter pylori, Schist soma haemotobium, liver flukes, dietary deficiencies and excesses, and pollution. Identifying which individuals are at higher susceptibility to cancer once exposed to these factors is an important research objective. Effective education programs on decreasing exposures would be valuable.

Oral cancer represents approximately 3% of all cancers. This, however, translates to 30,000 new cases every year in the United States. The single greatest risk factor is tobacco. While cases of oral cancers are seen in patients who do not use tobacco, these constitute a very small percentage of all oral cancers. All forms of tobacco have been implicated as causative agents including cigarette, cigar, and pipe tobacco as well as chewing tobacco. In India and Sri Lanka, where chewing tobacco is used with betel nuts and reverse smoking (placing the lit end in the mouth) is practiced, there is a striking incidence of oral cancer. These cases account for as many as 50% of all cancers! Heavy alcohol usage is an additional causative factor. Lip cancer, while included in statistics for oral cancer, is more similar to skin cancers. Sun exposure is the primary cause of these, while pipe smoking is also a factor.

Mouth cancers are present in various forms. Any persistent white patch must be regarded as being suspicious. Additionally, velvety red patches, particularly those with white speckles, should be the areas of concern. Finally, any non-healing ulcer (erosion) merits evaluation. More often than not. these areas are painless. The tongue is the most common site of oral cancer. Typically, the side of the tongue (farthest back in the mouth) is involved. The floor of the mouth (that area beneath the tongue) is next in order of frequency followed by the insides of the cheeks with involvement of other areas showing a lesser incidence.

While self-examination is advised, some areas cannot be adequately viewed and, of course, there is no substitute for examination by a professional. The best method for detection is to have semi-annual check-ups by your dentist. Should an area of concern appear in between these appointments, arrangements should be made for examination. If your dentist has any concern or question, he or she will refer you to an oral and maxillofacial surgeon for evaluation and possible biopsy. Biopsy is a quick clinical procedure whereby a surgeon takes a sample of the tissue in the concerned area for examination under a microscope.

Certainly, it is best to err on the side of caution. However, every white area or ulcer in the mouth should not unduly alarm one since there can be a multitude of harmless causes.

As with any other cancer, treatment of oral cancer is best undertaken at the earliest stage. This maximizes chances of successful treatment. Smaller areas may be treated by radiation or surgery while larger areas will often necessitate combined therapy. Prevention, of course, is the best approach and can best be achieved by avoiding risk factors- refraining from all tobacco products and consuming alcohol in moderation.

TPatient presented with a painless white lesion
on the right lateral border of tongue

The White lesion has raised, well defined border,
punctations surface, rolled edges



Punctations are tips of capillary loops that
almost reach the surface of the epithelium.
These are caused by Human
Papillomavirus (HPV) inflammation or
low grade squamous intraepithelial lesion



Look for sharp edges of teeth and ascertained
if the lesion could have been caused by chronic masticatory trauma or sharp edges of tooth




The white lesion is not so obvious on the
dorsal surface. The classical location of the
squamous cell carcinoma of tongue is at the
ventral lateral border of the tongue as shown in
this picture. Clinician must have high index
of suspicion when this type of lesion was
presented in routine clinical examination



The differential Diagnosis : Condylata acuminata.
This has 3 forms: 1. Aflat acanthotic lesion;
2. Papillary form; 3. Inverted form. They are
usually a result of human papillomavirus
infection (HPV)



Risk factor of Oral Cancer
Human Papillomavirus infection (HPV)
Age >60
Ethnic group - Indian higher incidence
Habits - Smoking, Betal nut chewing
Poor diet (eg. Low intake of Carotenoids and other antioxidant Micronutrients)
Immunosuppresion
Screening
Salivary sample screening
High index of suspicion, Carefully inspect the lesion
Check for local traumatic factor from Sharp edges of tooth
Perform Biopsy
Hyperpigmented
Erythematous

Ulcerated

Acetowhite lesion
Biomarkers Associated with
Oral Cancer
Histopathologic and cytologic characteristics
General Chromosomal changes
Changes in growth regulations
Changes in proliferation
Changes in differentiation
Optical Markers
Histopathologic and Cytologic Changes
Abnormal size
Shape
Texture
Number
Pleomorphic nuclei
General Chromosomal Changes
Chromosome aberration
DNAAbnormality
Anueploidy
Changes in Growth regulation
Abnormal expression of tumour suppressor genes
Increased expression of oncogenes
Altered expression of growth factors and receptors
Altered synthesis of polyamines (eg. Ornithine decarboxylase)
Abnormal level ofarachadonicacid
Changes in Differentiation (Grading)
Grade 1 - Well differentiated
Grade 2 - Moderately well differentiated
Grade 3 - Poorly differentiated
Grade 4 - Anueplastic
TMN Staging
Carcinoma in situ
T1,NO, MO - Tumour confined, less than 2mm in diameter, no lymph node metastases
T2, NO, MO-Tumor confined, size greaterthan 2mm in diameter, no lymph node metastases
T1/2/3.N1, MO-Any size tumourwith unilateral lymph node metastases
N2 - indicates bilateral metastases
M1 - indicates any distant metastases
Differential Diagnosis
Benign cellular changes -Leukoplakia, erythemaplakia
Infection - White Candidosis
Reactive - Trauma, chronic irritation
Epithelial cell abnormalities
Cancer
Cytochemical Changes
Decresed in expression offibrillar proteins (eg. Cytokeratins, involucrin, cornifin)
Changes in cell-cell adhesion molecules or cell substrate adhesion Molecules
Altered expression ofglycoconjugates

 


 

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