The significance of cone biopsy resection margins.

This 12-year retrospective study examines the significance of margin involvement with dysplasia at cone biopsy in relation to follow-up. Of 300 cone biopsies, 123 (41%) had margin involvement. These cases of margin involvement were associated with more severe dysplasia (P less than 0.0001) and a higher chance of subsequent abnormal cytological follow-up (P less than 0.0001) and residual dysplasia at subsequent surgery (P less than 0.0001). Involvement of the endocervical margin at the initial cone biopsy was a sensitive predictor of future abnormality, with an incidence of subsequent abnormal cytology of 29% and residual disease of 82% in those undergoing further surgery. In those cases where the margins had been clear, the incidence of abnormal cytological follow-up was 8%, with 12% residual disease in those undergoing subsequent surgery. Margin involvement was a better predictor of residual disease at repeat surgery than abnormal follow-up cytology (positive predictive value, 79% vs 60%, respectively).