Cervical Screening

Question 1

How common is HPV infection?

Answer 1

Peak prevalence is 15-25 years
Prevalence declines with age
30% prevalence in young women

Question 2

What cancer is HPV linked to?

Answer 2

Cervix, penis, vulva/ vagina, anus, mouth and oropharynx

Question 3

Describe HPV infection in the cervix

Answer 3

Infects the basal cells of the epithelial surface
Micro abrasion allows infection to infect cells
Virus replicates using hosts cellular mechanism
Does not stimulate immune response or tissue trauma
Leads to disorganised cell replication and high grade lesions

Question 4

What is the timeline of HPV leading to cervical cancer?

Answer 4

90% have cleared papilloma virus infection
In 2 years can lead to persistent HPV infection or viral lesions
In 5 years can lead to pre-cancer potential - CIN 2/3
In 10-20 years then cervical cancer

Question 5

Describe taking screening samples

Answer 5

Person with a cervix aged 25-64 years
5 yearly smears
Liquid based cytology
Test for high risk HPV
If positive then triage with cytology

Question 6

Why was there a change to HPV testing for cervical screening?

Answer 6

HPV is more sensitive for high grade abnormalities
HPV is a more effective test for the future
5 year screening interval

Question 7

What are some features of the HPV test?

Answer 7

Cervical cells
Machine
Identifies infection - could be transient or CIN associated
Sensitive

Question 8

What are some features of the cytology test?

Answer 8

Cervical cells
Human interpretation
Identifies cellular changes - low grade and high grade
Specific

Question 9

What is a HPV test?

Answer 9

Molecular test on cells sampled on cervix
Identifies high risk HPV
Targets 14 high risk HPV types
Works on LBC samples
Hybridisation and PCR

Question 10

What is a cervical cytology sample?

Answer 10

If high risk HPV positive
Microscopic assessment of cells scraped from transformation zone
Look for abnormal cells
Indicate if have cervical intraepithelial neoplasia - CIN

Question 11

What is dyskaryosis?

Answer 11

Cytology of the cervix which is abnormal

Question 12

What are the nuclear features of abnormal cells?

Answer 12

Increased size and nuclear : cytoplasmic ratio
Variation in size, shape and course irregular chromatin
Nucleoli

Question 13

What are the categories of dyskaryosis?

Answer 13

Low grade (+borderline)
High grade

Question 14

What do koilocytes reflect?

Answer 14

HPV infection

Question 15

What happens next if positive for hrHPV and dyskaryosis?

Answer 15

Refer to colposcopy

Question 16

Describe colposcopy

Answer 16

Magnification and light to see cervix
Excludes obvious malignancy
Use of acetic acid - identifies limits of lesion, biopsy site and define area to treat

Question 17

What are some HPV related pathologies?

Answer 17

HPV infection
Precancerous changes cervical intraepithelial neoplasia (CIN)
Cervical carcinoma

Question 18

What does E6 and E7 protein products do in the HPV transformation zone?

Answer 18

E7 - prevents cell cycle arrest
E6 - inhibits cell death

Question 19

What are koilocytosis?

Answer 19

Cells with wrinkled nucleus and perinuclear halo
Multinucleation

Question 20

What are low risk types of HPV?

Answer 20

6, 11, 42 and 44
Genital warts and low grade CIN
Often transient and resolves

Question 21

What are high risk types of HPV?

Answer 21

16, 18, 31 and 45
Persistent infection increases risk of developing
High grade CIN and cancer

Question 22

How does HPV cause high grade CIN?

Answer 22

Persistent infection - viral DNA integrates into host cell genome, overexpression of E6 and 7, and deregulation of host cell cycle

Question 23

Describe cervical intraepithelial neoplasia

Answer 23

Invisible to naked eye
Disorganised proliferation of abnormal cells in squamous epithelium
CIN 1, 2 and 3

Question 24

What is CN1?

Answer 24

Low grade dysplasia - will regress

Question 25

What is CN2?

Answer 25

Moderate dysplasia - may regress

Question 26

What is CN3?

Answer 26

Severe dysplasia - unlikely to regress
Precursor of invasive cancer

Question 27

What is the treatment for CIN2/3?

Answer 27

Excise transformation zone of cervix - LLETZ
Ablate transformation zone of cervix - thermal or laser ablation

Question 28

What is the follow up after treatment of CIN?

Answer 28

Increased risk of cervical cancer so follow up LBC at 6 months for cytology and high risk HPV
Both negative then 3 year recall
If positive - colposcopy