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Oral Cancer - Ætiological Factors
More than 90% of Oral Cancer is Oral Squamous Cell Carcinoma (OSCC).

OSCC accounts for approx 2 - 4% of all cancers in the UK but is one of the most common cancers on the Indian
subcontinent.

Men are more frequently affected than women; most
OSCC patients > 40 and the incidence of  rises rapidly with
age.

The lower lip is the most common site & related to
actinic (sun / solar) damage.

The tongue (the sides especially further back [
postero-laterally]), is the most common site within the mouth.
The majority of OSCC involves the lateral border of tongue ± Floor of Mouth.  Why are these sites predisposed to
tumour development? Perhaps
carcinogens pool in saliva in the so called ‘graveyard’ or ‘coffin’ area and there is
increased permeability to these chemicals in these areas.
Heavy tobacco smoking & alcohol consumption tend to be associated with the development of OSCC; in India & SE
Asia,
betel & areca nut chewing may be more important.


Ætiological Factors for Oral Cancer

Carcinogens


Sunlight (lip only)

Infections


Mucosal Diseases


Genetic Disorders

  • Dyskeratosis congenita
  • Fanconi’s anæmia
Tobacco
Alcohol
Areca Nut / Betel
Syphilis (Syphilitic Leukoplakia / Glossitis)

Syphilitic leukoplakia, especially of the tongue dorsum is a feature of tertiary syphilis (rarely seen now) but the
malignant potential is high.

Carcinoma developing near the centre of the tongue dorsum is typically the sequel to syphilitic leukoplakia.  Given
the decline in
late-stage syphilis, it is exceedingly rare in this site now.
Candida (Candidal Leukplakia)

leukoplakias especially at the commissures.

It may be associated with an increased risk of malignant change.

Candidal Leukoplakia responds well to anti-fungals & the cessation of
smoking.  The
tongue dorsum is also a common site.
Human Papilloma Virus 16 (HPV 16)

HPV related cancers appear to occur on the tonsillar area, the base of
the tongue and the
oro-pharynx (non-HPV positive tumours tend to
involve the
anterior tongue, floor of the mouth, the mucosa that covers
the inside of the cheeks and
alveolar ridges).

In general, it appears that
HPV-positive tumours occur most frequently in
a younger group of individuals than tobacco-related malignancies.  They
occur more in white males and in non-smokers.  The
HPV-positive group
is the fastest growing segment of the oral cancer population.

It does not appear that the
HPV 16 acts synergistically with tobacco or
alcohol and represents a completely unique disease process.
Oral Lichen Planus

It is estimated that 1 – 4% of patients develop carcinomata after a decade.  Plaque-like & erosive OLP in unusual
sites (such as the
fauces & tongue) should be regarded with suspicion.
Sub-Mucous Fibrosis (SMF)

SMF affects those from the Indian sub-continent & SE sclerosis but limited to the oral tissues & without the immune
abnormalities.

Arecoline, a stimulant derive from the areca nut is thought to induce fibroblast proliferation & collagen synthesis.

Clinically, there is
symmetrical fibrosis (scarring) of the buccal mucosæ, soft palate & the inner aspects of lips.
Useful Articles:

Dental Protection.  Risk Management Module.  Oral Cancer.

Dental Update 2000. An Overview of the Prevention of Oral Cancer and Diagnostic Markers of Malignant Change.
1. Prevention

Dental Update 2000. An Overview of the Prevention of Oral Cancer and Diagnostic Markers of Malignant Change.
2. Markers of Value in Tumour Diagnosis

Preventive Dentistry 2006.  Oral Cancer - A Growing Concern.

Oral Oncology 2008.  Oral cancer prevention and control The approach of the World Health Organization.

Oral Oncology 2009.  Review.  Global epidemiology of oral and oro-pharyngeal cancer.

BMJ 2010.  Head & Neck cancer - Part 1.  Epidemiology, presentation & prevention.

JADA 2011.  Rise in Oral Cancer Linked to HPV, Study Shows

JADA 2011.  The Connection between HPV & Oroparyngeal Squamous Cell Carcinomas in the US.  Implications for
Dentistry

BDJ 2013.  HPV linked to a third of throat cancer cases

BDJ 2013.  Letters to the Editor.  Tongue Cancer Subgroup

Dent Update 2015.  Mouth Cancer for Clinicians Part 3. Risk Factors (Traditional - Tobacco)

Dent Update 2015. Mouth Cancer for Clinicians Part 4.  Risk Factors (Traditional - Alcohol, Betel & Others)

Dent Update 2015. Mouth Cancer for Clinicians Part 5.  Risk Factors (Other)

BDJ 2018.  Oral Cancer & Tobacco - Developments in Harm Reduction

BDJ 2018.  The Changing Epidemiology of Oral Cancer - Definitions, Trends & Risk Factors
Last Updated 27th December 2019
In view of the commonplaceness of OLP, its importance as a pre-malignant lesion may be considerable.

Cutaneous LP appears to carry no risk of malignant change.
The overlying mucosa may be normal or there may be a vesiculating stomatitis.  Fibrosis & ishæmia causes
extreme pallor of the affected area which becomes so hard that it can’t be indented by your finger.

Progressive
trismus making it very difficult to eat / drink.  Malignant change is from 4.5 – 8 %.
National Statistics for Head & Neck Cancer in the UK, 2015 - 2017