Cervical cancer screening, HPV vaccination and testing Flashcards
1
Q
HPV - overview
A
- Types 16 and 18 account for 60-80% of all cervical cancer
- Infection with high-risk or oncogenic HPV (hrHPV) is necessary for cervical cancer development (virtually all cervical cancers test positive for HPV DNA)
- Natural hx: majority of low-grade lesions (LGSIL) regress without tx, whilst most high-grade lesions (HGSIL) progress to invasive cancer if left untreated. Typically takes 7-10y to develop invasive cervical cancer from CIN III
- Very common in sexually active males and females
- Acute infection -> clinically evident or subclinical infection -> clinically evident disease = warts, CIN
2
Q
HPV - vaccines
A
Use virus-like particles (but no viral DNA)
- Gardasil (quadrivalent) = HPV 16, 18 for cervical cancer, and HPV 6 and 11 for genital lesions
- Cervarix (bivalent) = HPV 16, 18
3
Q
HPV - testing
A
Using a commercial RNA probe-ELISA kit
4
Q
Pap smears - screening program
A
- Women 18-70y who have ever had sexual intercourse
- Every 2y
Special circumstances
- Pregnancy - should not cause deviation unless known low-lying placenta
- Immunosuppression - annual Pap tests, colposcopy if detected abnormality
- If subtotal hysterectomy (i.e. cervix retained), continue with routine screening. If total hysterectomy, no further screening required
5
Q
CIN/new terminology
A
LGSIL = CIN I HGSIL = CIN 2 or 3
6
Q
CIN - overview
A
- Necessary precursor lesion for development of cervical carcinoma. Histological dx = loss of differentiation and maturation from the basal layer of the squamous epithelium upwards
- Needs persistent cervical infection with HPV to develop (high risk 16, 18, 31 and 45)
- CIN 1 = mildly atypical cellular changes in the lower third of the epithelium
- CIN 2 = moderately atypical cellular changes confined to basal 2/3 of epithelium
- CIN 3 = severely atypical cellular changes encompassing >2/3 of eptihelial thickness, and includes full thickness lesions (formerly called severe dysplasia or carcinoma in situ)
7
Q
CIN - risk factors
A
- Exposure to HPV - early first sexual experience, multiple partners, non-barrier contraceptive
- COCP
- High parity
- Smoking
- Immunosuppression
8
Q
Colposcopy
A
- Examination of cervix and lower genital tract with low power, stereoscopic microscope with attached light source
- Cervix and vagina cleaned of any blood and debris with NS
- Cervix inspected and 3-5% acetic acid applied; causes acetowhite epithelial changes in dysplastic cells
- Lugol’s iodine may be applied - taken up by normal cells; dysplastic cells iodine negative
- Directed punch biopsy to gain histological confirmation
9
Q
LGSIL - management algorithm
A
- Repeat in 12 mo
a. If low-grade again, colposcopy
- If high-grade disease excluded on colposcopy, repeat Pap in 6mo
- If high-grade disease, tx
b. If normal, back to Pap in 24mo - If over 30 and no recent Pap, repeat Pap in 6mo or colposcopy
10
Q
HGSIL - mx algorithm
A
- Colposcopy and biopsy
a. If high-grade disease confirmed, treat
b. If high-grade disease not confirmed, review in 3-6mo
11
Q
HGSIL - tx
A
- LEEP (loop electrocautery excision), or LLETZ (large loop excision of transformation zone)
- Laser surgery using invisible CO2 laser beam
- Cold knife cone biopsy for adenocarcinoma in situ only
- Electrocoagulation diathermy (ECD)
- Cryosurgery with N2O or CO2 (under-resourced countries)
12
Q
LLETZ - complications
A
Short-term
1. Haemorrhage
2. Infection
3. Vasovagal reaction
Long-term
4. Cervical stenosis (dysmenorrhoea and/or difficulty in follow-up)
5. Cervical incompetence and premature delivery (but evidence suggests absolute risk of adverse effect on neonatal outcome is very low)
13
Q
Follow up after tx of HGSIL (3)
A
- Review 4-6mo after treatment for Pap smear +/- colposcopy
- Review 12mo after treatment for Pap smear, colposcopy and HPV DNA testing
- Once two sets of tests are negative on two consecutive 12-monthly occasions, the woman may return to the usual 2-yearly screening interval (i.e. after 36mo after tx and all negative tests). If Pap test or HPV not negative, continue with yearly review
