Oral Cancer and Screening

Question 1

Define screening

Answer 1

Application of a test or tests to people who are apparently free from the disease in question in order to sort out those who probably have the disease from those who probably do not
Not intended to be diagnostic
Interprets the natural history of a disease at its asymptomatic stage when it is treatable and progression can be halted

Question 2

What are screening programmes?

Answer 2

Organised screening for disease, including provision for recall, referral, specialist tx and evaluation
Screening is a continuing process
People are screened at regular intervals

Question 3

What are the types of screening?

Answer 3

Mass population screening

• Large scale screening of population groups
• Usually by invitation

Selective screening
- Targeted screening of high risk groups

Opportunistic screening
- Examining individuals when they attend for some other, often unrelated, purpose

Question 4

What are the 10 principles of screening? - Wilson and Junger 1968

Answer 4

1. The condition is an important health problem
2. Its natural history is well understood
3. It is recognisable at an early stage
4. Tx is better at an early stage
5. A suitable test exists
6. An acceptable test exists
7. Adequate facilities exist to cope with abnormalities detected
8. Screening done at repeated intervals
9. Chance of harm is less than the chance of benefit
10. Cost is balanced against benefit

Question 5

Advantages of cancer screening?

Answer 5

Reduced mortality and morbidity
Reduced incidence of invasive cancers
Improved prognosis
Identify high risk groups = primary intervention
Reassurance for those screened negative
Cost savings

Question 6

Disadvantages of cancer screening?

Answer 6

Detection of cases already incurable may increase morbidity for some patients
Unnecessary tx for lesions which may not have progressed
Psychological trauma for those with a false positive screen
False reassurance for those with a false negative screen
Reinforcement of bad habits among those screened negative
Costs

Question 7

What screening programmes work?

Answer 7

Cervical, breast and colon cancer

Question 8

Cervical cancer screening?

Answer 8

Women 25-64
Smears detect abnormal cells
If positive - referral for specialist exam and biopsy
Re-screened every 3 yrs until 50 and then 5 yrs

Question 9

Breast cancer screening?

Answer 9

Women 47-73yrs 
Mammogram to detect abnormalities
If positive - exam and biopsy 
Rescreened every 3 yrs 
2-2.5 lives saved for every overdiagnosed cose

Question 10

Bowel cancer screening?

Answer 10

Male and females 60-75yrs, every 2 yrs
Home test for faecal occult blood to detect abnormalities
If positive - exam and biopsy
Many false positives

Question 11

Screening programmes that do NOT work?

Answer 11

Prostate

• Detected too early when not affecting health in lifetime
• High false positives = over tx

Lung
- Detected too late

Question 12

Criteria for screening?

Answer 12

Disease must be common and serious - incidence is increasing and usually diagnosed late
Disease must have a known natural history - we do not know enough about this
A good screening test must be available
Effective tx must be available
It must be cost effective

Question 13

Stages of oral cancer?

Answer 13

Keratosis - Dysplasia - Carcinoma

Question 14

Types of oral precancerous lesions?

Answer 14

Leukoplakia

Erythroplakia

Question 15

Leukoplakia features?

Answer 15

Overall about 5% become malignant within 5 yrs
About 1.5%/yr transformation
Still no reliable way to predict which lesions will develop carcinoma

Question 16

Clinical appearance of early carcinoma and percentage of which progresses to cancer?

Answer 16

Erythroplakic 90%
Leukoplakic 58%
- All white 13%
- White and red 23%
- Stippled 21%
Ulceration 14%

Question 17

How to screen for oral cancer?

Answer 17

Systemic visual examination of the oral mucosa

Positive screen for a white patch, red patch, ulcer of longer than 2 weeks duration

Question 18

Kerala study - what happened?

Answer 18

Participants screened by oral examination - positives referred to hospital
Health, habits and socioeconomic date recorded

Question 19

Conclusions of the kerala study at 9 years?

Answer 19

Oral visual screening can reduce mortality in high risk individuals BUT there was NO significant difference in the mortality rate
BUT a significant difference in men who smoke and drink alcohol in the mortality rate
= Potential of preventing at least 37,000 oral cancer deaths worldwide

Question 20

What percentage of people presented with late stage disease with oral cancer?

Answer 20

81%

Question 21

What percentage of patients with oral cancer present late and what is the mortality percentage with no screening?

Answer 21

60% present late

60% mortality

Question 22

What is the problem with screening for oral cancer?

Answer 22

Many false positives
Poor sensitivity
High specificity

Question 23

Is a good screening test available for oral cancer?

Answer 23

Yes dentists can detect disease
But more research needed
Current research directed at using brush biopsy cytology to identify screen-detected lesions that are most likely to be dysplastic

Question 24

Treatment and prognosis for oral cancer?

Answer 24

Prognosis is generally poor, less than 54% overall 5 yr survival
Associated with radical surgical treatment unless detected and treated early
If detected early prognosis and outcome are excellent with 90% 5 yr survival for stage 1 lesions

Question 25

Is it cost effective to screen the whole UK population?

Answer 25

No, opportunistic screening in primary care may be cost effective