Carbon dioxide laser therapy of cervical intraepithelial neoplasia: factors determining success rate.

Sixty patients with biopsy proven CIN were treated with CO2 laser. Severity of the lesion was equally divided among all three grades of CIN. All patients were biopsied immediately after laser therapy and at six and twelve weeks past treatment. Persistence or absence of disease was evaluated with respect to severity of disease, size of lesion, method of applying laser, whether the endocervical canal was involved, whether only the lesion or the entire transformation zone was lasered, and depth of laser effect. The persistence of disease was 36.7 percent after therapy. Success was not related to severity of disease, size of lesion, or whether the endocervical canal was involved. It was related to depth of coagulation necrosis, method of applying the laser bean, and if the entire transformation zone was treated.