Oral cancer environmental aetiology

Question 1

What kind of cancer accounts for 90% of all mouth cancers?

Answer 1

squamous cell carcinoma

Question 2

What anatomical features differentiate mouth to oropharyngeal cancer?

Answer 2

Anterior 2/3 tongue = oral cancer

Posterior 1/3, tonsils, soft palate = oropharynx cancer

Question 3

how many people die of mouth cancer?

Answer 3

1 person is lost to mouth cancer every 3 hours

Question 4

Risk factors of mouth cancer

Answer 4

Tobacco, alcohol, immunological defects, sunlight, previous cancer, genetic conditions.

Approx, 25% of case have no known risk factors.

Question 5

Alcohol and tobacco use oral cancer risk increase

Answer 5

Alcohol and tobacco use can increase chances of oral cancer by 24 times.

Question 6

How can the relationship between alcohol and tobacco be described in terms of oral cancer?

Answer 6

Synergistic relationship: alcohol acts as a solvent for the carcinogens within tobacco smoking.

Heavy smoker - 10x risk
heavy smoker & heavy drinker - 24x risk

Question 7

Where is the most common site for cancer of the tongue and why?

Answer 7

FOM as this is known as the sublingual “gutter” where saliva pools which will be full of carcinogens from alcohol and smoking.

Question 8

Aside for allowing them to sit in solution, how else can alcohol result in better penetration of the carcinogens when smoking?

Answer 8

Causes thinning or atrophy of the overlying mucosa making it more permeable to the carcinogens allowing them to enter the epithelial cell barrier easier.

Question 9

Chemicals compounds found in alcohol and tobacco that cause mutagenic change of tissues.

Answer 9

Tar, polycyclic aromatic hydrocarbons (Benzopyrene), carbon monoxide, arsenic, formaldehyde, acetaldehyde.

Question 10

how does number of cigarettes impact relative risk of mouth cancer?

Answer 10

cigs - relative risk
10 - 2.5
20 - 5
>20 - 5.5

Question 11

What is betel nut?

Answer 11

Indian culture where this seed chewed by people to release nicotine/cocaine like effects.

Chemicals include: calcium hydroxide.

Relative risk increased by 8.5 when used with tobacco.

Question 12

Pathogenesis of betel nut?

Answer 12

Build up of collagen

DNA damage - mutagenesis

Oral submucosis fibrosis

Question 13

What might you see clinically with a patient who’s been reverse smoking?

Answer 13

Lesions on the hard palate etc. as the lit end of the cigarette is inside the mouth.

Question 14

How does acetaldehyde present in tissues in the mouth?

Answer 14

Alcohol is metabolised by salivary glands, mucosa, and oral bacteria to acetaldehyde which is a mutagen and carcinogen.

Tobacco smoke, bacteria (shown to produce a small amount).

Question 15

What is the metabolic breakdown of alcohol in the mouth?

Answer 15

Question 16

what is the drinking culture of drinking like in scotland?

Answer 16

1/3 of Scots binge drink

Question 17

What aspects of a good diet can prevent oral cancer

Answer 17

Vitamin C and E, antioxidants, zine, beta-carotene, folate (low intake can result in thinning of mucosa)

Question 18

How long before you should be worried about a lip ulcer?

Answer 18

3 weeks

Question 19

How could UV light cause mouth cancer?

Answer 19

Predominant effects would be on the mucosa of the lips