Screening for Cervical Cancer

1. Screening for Cervical Cancer Max Brinsmead PhD FRANZCOG September 2012

2. Cervical Cytology • As a screening test for Ca Cx this test has only ~75% sensitivity • Better at detecting CIN • but then specificity is a problem • Must sample the squamocolumnar junction • More significant if +ve in a high risk individual • Older • Early sex, multiple partners, other STDs • Smoking • HPV infection with high risk subtype • Liquid-based cytology can enhance sensitivity by ≈5% • Start at age 20 or within 3 years first coitus

3. Cytological Terms • LGEA = Low grade epithelial abnormality • Mostly due to HPV • Also called low grade squamous intraepithelial lesion or LSIL • HGEA = High grade epithelial abnormality • Arises from CIN1 & CIN2 (but these are histological terms) • Also called high grade squamous intraepithelial lesion or HSIL • Both the above have “Possible” variants • That is “Possible LGEA” and “Possible HGEA”

4. Colposcopy • Limited by need for expert and equipment • Relatively expensive • Subjective • Limited to visible part of the Cx • CIN can be masked by HPV • Of most use in identifying area for biopsy • Better therefore than previous alternative of cone biopsy

5. Histology • The gold standard for diagnosis • Only as good as the sample received • (except for cone or LLETZ) • And still somewhat subjective • But accuracy is increased if stains for high risk HPV DNA is used

6. Natural History of CIN • Progression 123cancer is not inevitable • CIN 1 - 85% spontaneously regress • CIN 3 – 50% regress or stay the same • Progression time varies • 6m to 16 years • But some will have invasive Ca when Pap smear reports only LGEA

7. HPV Subtyping • 90% of Ca Cx is associated with High Risk HPV • Subtypes 16,18,45,31,33,35,52,58 etc • Highly sensitive for the detection of HGEA • Does not require equipment or expertise • Equivocal results can occur • Of most use in the follow up of treated CIN • And those patients with persisting LGEA on Pap smear

8. Treatment Options for CIN • Observation • LGEA • Young women • Obvious HPV infection • Chronic LGEA with Low risk HPV subtype • Targeted destruction • Laser • Diathermy • Cryotherapy • Excision of the Squamocolumnar Junction • LETZ • Cone Biopsy • Hysterectomy

9. Follow up of CIN • 90 – 95% will be “cured” forever • Pap smears • Repeated until negative • 12 monthly for 2 years • Colposcopy • Ideally at lease once 6m after the procedure • HPV High Risk subtyping • Perform 12m and 24m after the procedure • High negative predictive value • Obstetric implications of treated CIN debatable

10. Current NH&MRC Guidelines • Repeat Pap once 12m after the first or if no tests for 5 years. Thereafter 2 yearly • Unsatisfactory Pap • Treat as required • Repeat in 3m • Send for colposcopy if 3 consecutive unsatisfactory • For LGEA • If <30 years repeat in 12 months • If >30 refer for colposcopy or repeat in 6m • For HGEA • Send for colposcopy

11. Prevention of CIN and Genital Warts • Polyvalent vaccines (types 6,11, 16 & 18) • Provide 90 – 100% protection from persistent infection, 16/18-related CIN2-3, adenoCa in situ and Ca Cx • Also protects against genital warts caused by the low risk HPV subtypes 6 & 11 • Therapeutic vaccines also under study • Optimal age for immunisation and need for boosters under evaluation • Male immunisation has started

12. Counselling a Patient with a Positive Pap Smear • This is not cancer • It is pre cancer • It is the whole point of doing Pap tests i.e. to detect and treat pre cancer so as to prevent it becoming cancer • Just like watching /removing “moles” of the skin • Not all pre cancer becomes cancer • It is a common condition • 40 – 50% of ♀ not immunised at some time in their life • STD basis not helpful but may need to be addressed • The Pap test is not diagnostic • Only a well-directed biopsy can be used for Rx decisions