cervical screening

Question 1

how is HPV transmitted

Answer 1

close, intimate contact i.e. penetrative sex

Question 2

HPV pathophysiology

Answer 2

selectively infects basal cells of epithelial surface so there needs to be some sort of micro-abrasion/trauma to epithelium to allow virus access to basal cells

virus replicates using hosts cellular mechanisms

final particles assemble in outermost layer in mature keratinocytes, which then decimate releasing viral particle

Question 3

how can HPV cause a cancer

Answer 3

occasionally, the viral DNA will become integrated with the host DNA resulting in disorganised cell replication and high grade lesions
if these lesions are not detected and treated there is a risk they can invade the basemen t membrane and become an invasive cancer

Question 4

persistence of HPV infection

Answer 4

can result in viral lesions/low grade changes which can be detected through cytology, often regress back to normal

persistence of high risk HPV can result in cervical intra-epithelial neoplasia (CIN). CIN grades 2 and 3 have potential to progress to a cancer

Question 5

prevention methods of cervical cancer

Answer 5

prevent HPV infection - primary prevention

detecting pre-cancerous changes and treating them so they don’t progress to cancer - secondary prevention

Question 6

which zone of cervix do we want to sample during cervical smear

Answer 6

transformation zone

Question 7

taking a screening sample

Answer 7

person with cervix aged 25-64yrs

test for high risk HPV

5yrs interval

if HPV positive triage with cytoolgy

Question 8

cervical cytology sample

Answer 8

only if high risk HPV +ive

microscopic assessment of cels scraped from transmission zone

look for abnormal cells

Question 9

dyskaryosis

Answer 9

abnormal cells

Question 10

nuclear features of abnormal cells

Answer 10

inc size and nuclear:cytoplasmic ration
variation in size and shape
coarse irregular chromatin
nucleoli)

Question 11

low grade (+ borderline) dyskaryosis

Answer 11

borderling where no definitive dyskariosis but changes to cytologisyt cannot mark as negative

Question 12

colposcopy

Answer 12

magnification and light to see cervix
exclude obvious malignancy

use of acetic acid +/-lodene

Question 13

options for management

Answer 13

punch biopsy to make diagnosis
-2mm sample

return for Rx if biopsy CIN2/3

see and treat first visit

Question 14

HPV in transformation zone of cervix

Answer 14

infects basal layer cells and utilises host for replication

as host cell matures, different viral genes are expressed

• E7 protein product - prevents cell cycle arrest
• E6 protein product - inhibits cell death

Question 15

HPV histology: koilocystosis

Answer 15

cells with wrinkled nucleus and perinuclear halo

multi-nucleation

Question 16

low risk HPV types

Answer 16

6, 11, 42, 44

genital warts and low grade CIN

often transient and resolve

Question 17

CIN

Answer 17

pre-cancerous changes cervical intraepithelial neoplasia

Question 18

high risk HPV types

Answer 18

16, 18, 31, 45

persistent infection

overexpression of viral E6 and E7 proteins, deregulation of host cell cycle

high grade CIN and (more rarely) cancer

Question 19

histology CIN3

Answer 19

neoplastic cells or undifferentiated cells fill full thickness of epithelium
no normal differentiated cells seen

Question 20

histology CIN2

Answer 20

undifferentiated cells occupy 2/3 of thickness and only top layers show maturation to medium size cells

Question 21

histology CIN1

Answer 21

undifferentiated cells only occupy lowest 1/3 of epithelium and surface cells can mature to big flat cells

Question 22

cervical intraepithelial neoplasia

Answer 22

disorganised proliferation of abnormal cells in squamous epithelium (dysplasia)

lack of maturation, variation in cellular size and shape, nuclear enlargement, irregularity, hyperchormasia, cellular disarray

precursor of invasive cancer

Question 23

treatment of CIN2/3

Answer 23

excise transformation zone of cervix

ablate transformation zone of cervix

Question 24

follow up after treatment of CIN

Answer 24

to confirm treatment was effective - if detect CIN after 2yrs Rx would be residual disease

to prevent invasive cancer

to reassure woman her Rx worked

increased risk cervical cancer compared with normal population

follow up LBC at 6mo for cytology and high risk HPV

• both - then return to 3yrs re call
• either + then colposcopy

Question 25

what next step if a) cytology normal b) cytology abnormal

Answer 25

normal then repeat 1 year

abnormal then colposcopy