Is colposcopy needed following laser ablation for dysplasia?

To evaluate the effectiveness of cytology and colposcopy in the follow up of women treated by laser CO(2) ablation for cervical intraepithelial neoplasia (CIN).

A retrospective analysis of 1784 patients with CIN treated with laser CO(2) ablation from 1998 to 2003 at the Royal Women's Hospital, Melbourne. Data were collected prospectively in a computerised colposcopy database utilised in the Dysplasia Unit.

There was equal distribution in the study population treated for low-grade intraepithelial neoplasia (LSIL) and high-grade intraepithelial neoplasia (HSIL), with no significant age difference in both groups (mean 27.6 years). The success rate of treatment of LSIL (94%) was similar to that of HSIL (92%). Fifty-seven per cent of all failures occurred within the first year of treatment. Colposcopy was more sensitive in detecting intraepithelial neoplasia (SIL) than cytology, whereas cytology was more specific. No case of cancer was diagnosed on follow up.

CO(2) laser ablation was equally effective in treating different grades of CIN. There is a continuing incidence of recurrent CIN, even up to five years after initial treatment, which suggests that it is necessary for patients to adhere to long-term follow up. The combination of cytology and colposcopic assessment is essential for surveillance of SIL in the initial two years after treatment.