Persistent intraepithelial neoplasia after excision for cervical intraepithelial neoplasia grade III

To determine the factors associated with subsequent intraepithelial neoplasia among patients who had cervical intraepithelial neoplasia grade III (CIN III) diagnosed on a specimen from previous large-loop excision of the transformation zone.

We studied all large-loop excisions of the transformation zone performed between May 1991 and December 1993, inclusive. All cases of CIN III were identified. We followed up patients with cytology and colposcopy for 2 years after treatment for high-grade CIN. Findings at follow-up were analyzed.

A histologic diagnosis of CIN III was made in 225 patients. The lesion appeared incompletely excised in 105 patients (48.2%). In 76 cases (34.9%), CIN III was found at the endocervical margin. Of the 211 patients reviewed at 6 months, 18 (8.5%) had histologically proven CIN. The incidence of CIN was 16.5% after a report of incomplete excision, compared with 1.9% after a report of complete excision (P < .001). Furthermore, there was no subsequent CIN III in the complete-excision group. Of the 183 patients reviewed at 24 months, seven (3.8%) had histologically proven CIN. All cases of subsequent CIN were associated with dyskaryosis on follow-up cervical cytology.

Positive margins increase the risk of treatment failure. Cytology alone may be adequate for follow-up when CIN III is completely excised.