Persistent intraepithelial neoplasia after excision for cervical intraepithelial neoplasia grade III.

OBJECTIVE: 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.

METHODS: 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.

RESULTS: 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.

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