The programme
- Persistent infection with high-risk HPV (16 and 18 in about 70 percent of cancers) causes cervical intraepithelial neoplasia at the transformation zone over years; screening finds it before invasion.
- Canadian provinces are moving from cytology every 3 years (from age 21 or 25) to primary HPV testing every 5 years (from 25 or 30), with self-sampling in several programmes. Intervals and start ages differ by province; check the programme, not a memory.
- HPV vaccination (9-valent) is routine in school programmes and offered to adults to age 45; it prevents the infections that cause most cervical, anal, oropharyngeal and vulvar cancers.
- Screening stops around 65 to 70 with an adequate negative history; it is not needed after a hysterectomy for benign disease with the cervix removed.
The abnormal result
- Colposcopy: acetic acid turns dysplastic epithelium white; Lugol's iodine is not taken up by it. Biopsy the worst area. CIN 1 is watched; CIN 2 or 3 is treated by LEEP (loop excision) or ablation, with a small increase in preterm birth risk after excision.
- In pregnancy, screening is done if due and colposcopy is safe; treatment is deferred unless invasion is suspected.
| Result | Next step (typical programme) |
|---|---|
| HPV negative | Routine recall |
| HPV positive, cytology normal | Repeat in 12 months; colposcopy if persistent |
| HPV 16 or 18 positive | Colposcopy |
| ASC-US, LSIL | HPV triage or repeat cytology; colposcopy by programme rules |
| ASC-H, HSIL, AGC | Colposcopy (and endocervical or endometrial sampling for AGC) |
Watch it done
Consent, positioning, speculum, brush sampling and the liquid-based cytology vial.
On the modelCervix