Cervical Cancer Flashcards
Where cervical cancer rank on worlds most frequent cancers?
4th
What % of cervical cancers are related to HPV type 16/18?
71%
What instruments are required for a conventional pap smear?
Bivalve speculum Adjustable light Cervex sampler or ayres Microscope slide Spray fixative Pencil to label slide
What instruments are required for liquid based specimens?
Hologic Thin prep
BD surepath
What is the aetiology of SCC?
Sexually transmitted disease
HPV infection most likely cause
What are some risk factors for SCC?
Sexual activity
- Early coitus age - Multiple partners
Exposure to high risk males
- Early age of first coitus - Multiple partners - Cigarette smoking - Prostatitis - Penile HPV infection - Carcinoma of penis
Drugs
- Ciggies
- Pill
- Immunosupressive drugs
- Alcohol
- Diethyl stilboestrol
- HPV and HSV infection
- Low socioeconomic
What evidence is there for HPV causing SCC?
HPV DNA in more than 80% of carcinomas
HPV DNA in other tumours
How many HPV genotypes are there?
> 100
40 commonly infecting genitals
15 carcinogenic
What are the main high risk HPV genotypes?
16, = worst = 50% all cancers 18, 31, 33, 4 5
What are some low risk HPV genotypes?
6
11
40
What are the two primary viral oncogenes of HPV?
E6 and E7
What does E6 do?
Binds and inhibits p53, inhibing mitosis
Activates telomerase allowing cells to replicate continuously
What does E7 do?
Binds retinoblastoma protein (pRb), inactivating transcription factor E2F
Cell can evade cell cycle at G1/S1 transition phase
How does HPV infect humans?
Infects cells of basal layer of peithelium at junction between vagina and ectocervix
E1 and E2 proteins in basal layers
E6 and E7 at distal layers
When are E1/E4 proteins and L1 and L2 late proteins expressed?
As infected cells differentiate into squamous cells
These represent koilocytes seen on cytology
Where are koilocytes seen?
Intermediate and superficial squamous cells (E1 and E4 fusion proteins)
Dense peripheral polychromatic cytoplasm
Nuclear enlargement and hyperchromasia, multinucleation and binucleation
What types of vaccination for HPV is there?
Tetravalent, HPV, 6, 11, 16 and 18 (Gardasil)
Bivalent HPV 16 and 18 (Cervarix)
What types of Squamous Cell carinomas are there?
Non-keratinising SCC (50%)
- Large cells, may be few keratinising
Keratinising SCC (35%) - Well differentiated SCC, single keratinised squamous
Small cell Sq carcinoma (15%)
- Uncommon, poorly differentiated SCC
What is the cytology of keratinising SCC?
Tumour cells
- Similar size
- Pleomorphic
- Round, oval, polygonal, spindled
- Keratinised cytoplasm
Nuclei
- Usually no nucleoli
- Coarsely granular chromatin or pyknotic
- often large
How is SCC diagnosis made?
Cant usually on pap smear
Requires coolposcopy, biopsy
What is prognosis for SCC?
15-85% 5 year surv depending on tumour stage
What does the cervical cytology registry do?
The CCR maintains and operates:
- Database of pap + other cervical screening test
- Governed by legislation
- 4.5 mill test results
Safety net-sends reminders to women to get pap Follows up abnormal results Linked historys to screening Clinical support to women Stats + research Planning monitoring + evaluation Quality assurance data
