Cervical Screening Symposium Flashcards
What cancers are largely caused by HPV?
Cervix
Penis
Vulva/vagina
Anus
How does HPV infect?
Passes into micro-abrasions in the epithelium - invade basal cells
How does HPV infection become pre-cancerous?
Virus DNA with cell DNA invades other cells
Leads to more damage and disorganisation
Grows to full thickness
How are people immunised against HPV?
2 dose regimen
What is the SCCRS?
Scottish Cervical Call Recall System Smear taker enters request details Vials sent to lab (added to SCCRS) Patient details received, vials stained Cytology lab puts results on SCCRS Woman + GP receive results
How does the cervix change in puberty?
Increased vascularity and interstitial fluid
Glandular epithelium metaplasia to squamous epithelium
Why does vaginal glandular epithelium undergo metaplasia in women going through puberty?
Response to increased acidity in the vagina
Which part of the cervix is susceptible to HPV? Why?
Transitional zone
Large amount of cell turnover here
How are women screened for cervical cancer?
Smear every 5 years
How are cervix samples tested?
Liquid based cytology
HrHPV test
(If +ve) - Reflex Cytology
How does the HPV test work?
Identifies HPV type using viral DNA and RNA
High risk type > specific genotyping
How are cervical cytology samples tested?
Cells scraped from transformational zone
Look for dyskaryosis
Look for underlying CIN
What is CIN?
Cervical intraepithelial neoplasia
What is dyskaryosis?
Abnormal cells
What are the different epithelium of the cervix?
Endocervix - columnar epithelium
Ectocervix - squamous epithelium
How are cervical samples processed?
Thin layer of cells with PAP smearing
What features suggest dyskaryosis?
Nucleus:
- Increased size
- Increased Nuclear:cytoplasmic ratio
- Variation in size/shape
- Coarse irregular chromatin
- Nucleoli
What do different grades of dyskaryosis reflect?
Degree of underlying CIN
What do Koilocytes suggest?
HPV infection
How do HPV tests and Cytology differ?
HIV test: - Cervical cells - Identifies infection - Sensitive Cytology: - Cervical cells - Cellular changes (grading) - Specific
What happens next if a patient has a negative HrHPV?
Routine recall in 5 years
What happens next if a patient has a positive HrHPV?
Cytology normal - repeat in 1 year
Dyskaryosis: refer to colposcopy
What is the process for colposcopy?
Education and Advice
Magnification + light on cervix
Acetiv acid + iodine
What is the benefit of colposcopy?
Identify limits of lesion
Biopsy site
Showing CIN/metaplasia
How is CIN managed?
Low grade - return
High grade - treat
What is the function of HPV E7 protein?
Prevent cell cycle arrest
What is the function of HPV E6 protein?
Inhibit cell death
Which cells does HPV infect?
Basal cells
What is Koilocytosis?
Cells with wrinkled nucleus and perinuclear halo
Multinucleation
What are the main low risk types of HPV?
6, 11, 42, 44
What are the main high risk types of HPV?
16, 18, 31, 45
What do low risk HPV types cause?
Genital warts
Low grade CIN
Transient infection
What do high risk HPV types cause?
High grade CIN/Cancer
Persistent infection
How does high grade HPV cause CIN?
Persistent infection
Viral DNA integrates into host cell genome
Overexpression of viral E6 and E7 proteins
Deregulation of host cell cycle
How does high grade CIN present histologically?
Neoplastic/undifferentiated cells fill full thickness of epithelium
What is CIN?
Disorganised proliferation of abnormal cells in squamous epithelium
Precursor to cancer
How is CIN treated?
LLETZ
Thermal coagulation
Laser ablation
How is CIN treatment followed up?
Confirm treatment was effective Prevent invasive cancer Reassure the woman Increased risk of cervical cancer Follow up LBC at 6 months (cytology - high risk HPV)
How is the patient managed if her follow-ups are both negative?
Return to recall (every 5 years)
How is the patient managed if either of her follow-ups are positive?
Return to colposcopy
