DOES COLPOSCOPICALLY DIRECTED PUNCH BIOPSY REDUCE THE INCIDENCE OF NEGATIVE LLETZ

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.