Long Term Outcomes of Laser Conization for High Grade Cervical Intraepithelial Neoplasia in Thai Women

Aim: To report long term outcomes of laser conization for high grade cervical intraepithelial neoplasia (CIN)in Thai women. Materials and
Methods: A retrospective cohort study was conducted in patients undergoing laserconization due to abnormal cervical cytology suggesting neoplasia during 1989 to 1994 and having follow-up datauntil December 2010. Conization was performed under colposcopy using a 0.5-mm CO2 laser beam with powerdensity of 18,000-20,000 watts/cm2, and the surgical base was vaporized using a low power defocused beam. Thefollow-up protocol included cervical cytology and colposcopy. Long term outcome measures were failure rate(persistence and recurrence), post-conization status of transformation zone, and obstetric outcomes.
Results:Of 104 patients undergoing conization, 71 had therapeutic conization for high grade CIN and were followed upfor a median time of 115 (range 12-260) months. There was one case of persistent and one of recurrent diseasecomprising a failure rate of 2.8%. The post treatment transformation zone was well visualized in 68.3% of 63patients with an intact uterus. Sixteen patients achieved 25 pregnancies; none had second trimester miscarriage.The obstetric outcomes were unremarkable.
Conclusions: Laser conization under colposcopic visualization for thetreatment of high grade CIN in Thai women has a low failure rate of 2.8%. The post-conization transformationzone could not be evaluated completely in approximately 30% of cases; therefore the follow-up protocol shouldinclude both cytology and colposcopy. Obstetric outcomes are not adversely affected by this therapeutic procedure.