Exodontia.Info
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)

Candidal infection is common in speckled
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)
Last Updated 5th May 2016
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 %.