Cryosurgical treatment of cervical intraepithelial neoplasia: four-year experience.

Cryosurgical therapy was used to treat 393 patients with cervical intraepithelial neoplasia. Therapeutic success was evaluated in relation to lesion size, grade, and endocervical extension. The overall cure rate with cryosurgical therapy was 84%. Size alone was found to be the major determinant of cryosurgical success. For one-quadrant lesions, there was a 99% cure rate. For two-quadrant lesions, the cure rate was 93%. For three- or four-quadrant lesions, the success rate was only 61%. Lesion size was found to be positively correlated with grade of dysplasia. As the grade of cervical intraepithelial neoplasia progressed, lesion size tended to increase. When this association was controlled for, grade of dysplasia was not a significant determinant of success rate. When endocervical extension occurred, although the upper limits of the lesion were seen, there was a significantly reduced success rate of 64%. Patients with large lesions or endocervical extension are at a much higher risk for failure with cryosurgical treatment. If cryotherapy is chosen for these patients, careful, long-term follow-up is essential to ensure adequate treatment of disease.