Does colposcopically directed punch biopsy reduce the incidence of negative LLETZ?

Abstract

OBJECTIVE: To evaluate the role of punch biopsy in reducing the occurrence of negative histology provided by large loop excision of the transformation zone in the management of cervical intraepithelial neoplasia. DESIGN: Retrospective review of computerised data base and clinic files. SETTING: Colposcopy Clinic, Groote Schuur Hospital, Cape Town, South Africa. SUBJECTS: Two hundred and ninety-eight women considered suitable for the local outpatient management of cervical intraepithelial neoplasia. METHODS: Two groups of patients were identified: group A consisted of women who had cervical intraepithelial neoplasia confirmed colposcopically and who underwent directed punch biopsy; group B consisted of women who had cervical intraepithelial neoplasia confirmed colposcopically and were referred for large loop excision of the transformation zone without confirmatory punch biopsy. RESULTS: In Group A (n = 184) 123 women had cervical intraepithelial neoplasia diagnosed on punch biopsy. Large loop excision of the transformation zone was performed on 116 women and 7 were lost to follow up. The procedure confirmed cervical intraepithelial neoplasia in 95 cases (82%), but there was no cervical intraepithelial neoplasia in 21 cases (18%). Sixty-one women had negative punch biopsies. Of these, 13 underwent large loop excision of the transformation zone, 31 had persistently negative follow up cytology, and 9 had positive cervical smears of which 7 were treated with large loop excision of the transformation zone, and 8 were lost to follow up. Overall, 25% of all negative punch biopsies were falsely negative. In group B 114 were treated with large loop excision of the transformation zone and cervical intraepithelial neoplasia was confirmed in 97 cases (85%); one woman had unsuspected microinvasion (1%) and 16 women (14%) had no cervical intraepithelial neoplasia. Negative histology after large loop excision of the transformation zone was not statistically different in groups A and B. CONCLUSION: Punch biopsy does not reduce the occurrence of negative histology after large loop excision of the transformation zone.