Cervical Screening Flashcards
What percentage of human cancers are caused by viruses?
12%
What viruses are associated with the development of cancer?
HPV
HIV
EBV
HBV
When do most people pick up HPV?
In late teens/early 20s, peak prevalence 15-25 years
Why does prevalence of HPV decline with age?
Due to body clearing the virus, cervix maturing and less susceptible to changes, and reduced number of exposures to people with HPV
What is the overall prevalence of HPV?
10%
What is the prevalence of HPV in young women?
30%
What is the lifetime risk of exposure to HPV?
Up to 75% (from serological studies)
What cancers is HPV implicated in?
Cervix Penis Vulva/vagina Anus Mouth Oropharynx
Why does there need to be some break in the epithelium in order for HPV to infect the basal cells?
HPV can only infect basal cells and the basal layer is usually protected by an epithelial layer
When can HPV disrupt normal cell division and cause pre-cancerous changes?
If it becomes integrated in the nucleus
What percentage of people with HPV will clear the virus with their normal immune system?
90%
What can persistent HPV infection result in?
Viral lesions (CIN1, CIN2 or CIN3) CIN1 lesions may regress, remain unchanged or progress to CIN2, CIN3 or cervical cancer
In what percentage of patients aged 15-34 years and 35+ years is regression to CIN1 to dysplasia estimated to occur?
65% in 15-34 year olds
40% of patients aged 35 or older
How long does it take most low-grade SIL to clear?
6-12 months
What is primary prevention and secondary prevention of HPV?
Primary prevention with immunisation
Secondary prevention with cervical screening
What is the UK HPV immunisation programme?
Introduced September 2008
Girls born after 1st September 1990 are offered bivalent vaccine HPV16/18
From September 2012 - quadrivalent vaccine HPV 16/18/6/11
From September 2014 - 2 dose regime
What is the additional benefit of the high uptake of HPV immunisation in Scotland?
Herd immunity
Immunisation against HPV reduces the risk of what cancers?
CIN and cervical cancer
What countries have the highest uptake of HPV vaccination?
Countries with the lowest rates of cervical cancer are those with the highest uptake of the vaccination
What is opportunistic screening of HPV?
When a smear test is offered by chance to a woman coming into surgery/clinic for another reason
When was organised screening brought in?
1989-1991
What is the process of the Scottish Cervical Cell Recall System?
Smear taker enters request details on to SCCRS database
Vials sent to lab, receipt logged on SCCRS
Patient details received from SCCRS, vials processed, slides stained and screened
Cytology lab results put on SCCRS database
SCCRS creates colposcopy referral
Woman and GP receive results
At what ages are screening samples for cervical cancer taken?
Women aged 25-64 years
3 yearly smears up to age 50
5 years from age 50
(liquid based cytology)
What is cervical cytology?
Microscopic detection of abnormal squamous cells that are suggestive of underlying cervical intraepithelial neoplasia
Identify women that have no abnormality and those requiring further investigation