Screening Programmes

Question 1

What is a screening programme?

Answer 1

• A test offered to an asymptomatic person to detect those who have a high probability of having a disease.
• It is not a diagnostic procedure and those with a positive test need further investigation.

Question 2

What are the different epithelias in the cervix?

Answer 2

• Ectocervix; sqamous epithelium, only bottom layer should contain dividing cells
• Endocervix; single layer of cuboidal cells containing mucin, no visible cell division.

Question 3

What does microabrasion or epithelial trauma to the cervix do?

Answer 3

IT exposes part of the basement membrane, allowing virus entry.

Question 4

What is the 1st to 3rd requirement for a screening programme?

Answer 4

1. Condition should be an important problem for the individual and for the community.
2. There should be an accepted treatment for patients with the disease.
3. Facilities for diagnosis and treatment should be available.

Question 5

What are the 4th to 6th requirement for a screening programme?

Answer 5

4. There should be a recognisable latent or early stage.
5. There should be a suitable test or examination.
6. The test should be acceptable to the population.

Question 6

What are the 7th to 10th requirements for a screening programme?

Answer 6

7. The natural history of the condition, including development from latent to declared disease, should be adequately understood.
8. There should be an agreed policy on who to treat as patients.
9. The cost of the case finding programme should be economically balanced in relation to expenditure on medical care as a whole.
10. Case finding should be a continous process

Question 7

What are some more requirements of screening programmes?

Answer 7

• These should be q quality assurance, with mechanisms to minimise potential risks of screening.
• Programme should ensure informed choice, confidentiality and respect for autonomy.
• Programme should promote equity and access to screening for the entire target population

Question 8

Describe the pathophysiology of cervical cancer?

Answer 8

• Majority of cervical cancers have a high risk subtype of human papilloma virus (HrHPV) as an underlying cause.
• Persistant infection with HrHPV can cause changes in cells which in some people progresses to cancer.

Question 9

What are some more risk factors of cervical cancer?

Answer 9

• Smoking
• Poor immune function
• Multiple sexual partners

Question 10

What is HPV, who does it usually infect and what tends to be the outcome?

Answer 10

• HPV are a group of DNA viruses, which are grouped into high and low risk.
• 80% of sexually active people will become infected at some point during their lifetime.
• Most clear it with no intervention

Question 11

Where does the virus enter the cervix and how does it mature?

Answer 11

• Virus enters cervical epithelia at the transformation zone

- HPV replicates in maturing squamous cells producing koilocytes

Question 12

What happens in the high risk subtypes of HPV?

Answer 12

• Patients who have persisting infection with a high risk oncogenic subtype of HPV are at risk of developing pre cancerous changes and cervical cancer.
• High risk HPV subtypes incorporate their DNA into that of the host cell.

Question 13

What happens in low risk HPV subtypes?

Answer 13

Low risk HPV subtypes tend to result in free viral DNA within the cell.
-They are responsible for viral warts (eg. subtypes 6, 11, 42, 44)

Question 14

What are high risk HPV subtypes E6 and E7 responsible for?

Answer 14

They reactivate the cell cycle in cells which are not normally proliferating.

Question 15

What is the result of persistant infection disruption of the cell cycle by high risk HPV subtypes?

Answer 15

Results in proliferation of the epithelial cells without an external stimulus - precursor lesions for cervical cancer. These are termed CIN and CGIN.

Question 16

What is CIN?

Answer 16

• Cervical intraepithelial neoplasia

- Divided into CIN 1, 2, 3.

Question 17

What are the outcomes of CIN 1, 2 and 3?

Answer 17

• In most patients CIN 1 resolves without treatment, so patients are monitored.
• CIN 3 is the precursor lesion for squamous cell carcinoma (usually takes more than 2 years to develop into invasive carcinoma).
• Main purpose of cervical screening programme is to detect and treat CIN 2 and CIN 3.

Question 18

What is CGIN?

Answer 18

• Cervical glandular intraepithelial neoplasia.

- Much less common and is precursor lesion for adenocarcinoma

Question 19

Who is invited for cervical screenings?

Answer 19

Women aged 25-65 invited every 5 years

Women with abnormal tests called more frequently

Question 20

What are samples tested for in cervical screening?

Answer 20

• All samples get HPV testing

- 15% get cytology testing: samoles with positive HPV test, samples from patients on follow up pathways

Question 21

Describe HPV testing?

Answer 21

• Runs automated test for 14 high risk HPV subtypes
• Specific type found is not reported
• Negative: recall in 5 years
• Positive: tested for cytology

Question 22

Describe cervical cytology testing?

Answer 22

-Cells from transformation zone are spread out
-Abnormal cells have enlarged, irregularly shaped nuclei
This is called dyskaryosis and is graded as mild, moderate or severe depending on the size of the nucleus.
-These roughly equate to CIN 1, 2, 3 on histology specimens, biopsy needed to confirm degree of abnormality.
-Patients who have cell changes referred to colposcopy for investigation.
-Patients with positive HPV but no cell changes are called back in 1 year for repeat HPV test.

Question 23

Describe colposcopy?

Answer 23

• Uses specialist microscope, acetic acid applied to highlight any abnormalities
• Patients can have biopsies taken and treatments for abnormalities detected.

Question 24

Who is invited for breast screening?

Answer 24

-Women aged 50-70 are invited every 3 years for a mammogram, with the aim of detecting disease early.

Question 25

What is the process of breast screening?

Answer 25

-30 min appointment and 2 x X-rays are taken of each breast.

Images are interpretated an the results sent to the GP an patient.

Question 26

What is the process for those with abnormal breast screens?

Answer 26

-Those with abnormal or unsatisfactory results are seen at a specialist clinic for triple assessment: -clinical exam, radiology (repeat mammogram or ultrasound if needed), biopsy.

Question 27

What is normal breast tissue like compared to cancerous version?

Answer 27

Normal = ductile tissue, lobular tissue, adipose tissue, fibrous tissue
Cancer = fatty tissue has cells infiltrating between fat cells, no structure, ductules or lobules, variation in nuclei subtle

Question 28

What is the aim of bowel screening?

Answer 28

-Aim to detect precancerous changes (often polyps) and early cancers which are treatable and have better prognosis.

Question 29

Who is invited for bowel screening?

Answer 29

-Men and women aged 50-74 are invited to participate every 2 years

Question 30

What is the process of bowel screening?

Answer 30

-A faecal immunochemical test (FIT) is sent in post for completing at home.
-One sample of stool is collected and returned in a pre paid envelope.
This is tested for haemoglobin, results sent back within 2 weeks.
-If the level of haemoglobin is above 80ugHb/g faeces, patients are referred to colonoscopy.

Question 31

What is a polyp?

Answer 31

Are things that grow into lumen of tube and can be removed. They have disordered architecture.

Question 32

What is the histology of the bowel?

Answer 32

-Have tube like glandular cells lined by cells that make musin to lube stool.

Question 33

What is dysplasia histology?

Answer 33

Appears bluer, larger nuclei, glands close and arranged haphazardly.

Question 34

Describe the test for cervical screening?

Answer 34

• A cervical smear test:
• carried out at GP surgery/sexual health clinic
• brush used to remove cells from cervix
• these are transferred to a pot of preservative
• are tested for HPV +/- cytology