The prevention of cervical cancer Flashcards
which viruses are indicated in the progression of cervical cancer
HBV
HIV
EBV
HPV
How common is HPV infection?
peak prevalence 15-25yrs
prevalence declines with age
10% overall
~30% prevalence in young women
lifetime risk of exposure 80% from serological studies
how does HPV infection affect the cervix and how is this identified
Early HPV infections may be accompanied by mild changes in the epithelium.
An abnormal growth of squamous cells detectable on smear is called a squamous intraepithelial lesion (SIL). Such changes may be low grade (LSIL) or high grade (HSIL), depending on how much of the cervical epithelium is affected, and how abnormal the cells appear.
Abnormal cells in the cervix detected by biopsy and histological examination are classified as cervical intraepithelial neoplasia (CIN). Graded 1 to 3 according to the proportion of cervix affected.
what is the UK HPV immunisation programme
1 Sept 2008
Girls born after 1 September 1990
Bivalent vaccine HPV16/18
Sept 2012
Quadrivalent vaccine HPV 16/18/6/11
Sept 2014
2 dose regime
Boys included 2019
what components make up the Scottish cervical call system
smear taken enters details to SCCRS database
vials sent to lab receipt logged
patient details received vials screened by HPV testing
Lab results put on database
woman and gp received results
Why did we change to HPV testing for cervical screening?
HPV testing is more sensitive than cytology for high grade abnormalities
As more HPV-immunised women enter the screened population, cervical disease will decrease and will be more difficult to detect by cytology. HPV will be more effective test for the future.
If the HPV test is negative, the woman’s chance of developing cervical cancer in the next 5 years is very small, allowing a 5 year screening interval for all women regardless of age.
HPV test
Cervical cells
Machine
Identifies infection
Could be transient
or CIN associated
Sensitive
cytology test
Cervical cells
Human interpretation
Identifies cellular changes
Low grade - persisting infection/CIN1
High grade – CIN2/3
Specific
laboratory processing of cervical samples
Cells in the vial are tested
Hr HPV test (all)
If positive (15%) reflex cytology
What is an HPV test?
Molecular test on cells sampled from cervix
Identifies high risk HPV E6/7 mRNA
Targets 14 High risk HPV types (but screening test does not identify specific HPV types)
Works on LBC samples
Technology:
Hybridisation
PCR
Cervical cytology sample
only if high risk hpv
Microscopic assessment of cells scraped from the transformation zone
Look for abnormal cells (dyskaryosis)
indicate that woman may have underlying cervical intraepithelial neoplasia - CIN
DYSKARYOSIS
CYTOLOGY of the CERVIX
abnormal
Abnormal cells may be few
Nuclear features:
increased size and nuclear:cytoplasmic ratio
variation in size, shape and outline
coarse irregular chromatin
nucleoli
Graded low or high grade dyskaryosis - reflects degree of underlying CIN
Low grade (+ borderline)
High grade
what happens following cytology result
Negative for hrHPV – routine recall 5 years
Positive for hrHPV:
Cytology normal; repeat test 1 year
Dyskaryosis: refer to colposcopy
Colposcopy
Magnification and light to see cervix
Exclude obvious malignancy
Use of acetic acid =/- Iodene:
Identify limits of lesion
Select biopsy site
Define area to treat
management hpv
Punch biopsy to make a diagnosis
Return for Treatment if CIN2/3
“See and treat” at first visit
