A randomized trial of the Fischer cone biopsy excisor and loop electrosurgical excision procedure

Obstet Gynecol. 2004 Oct;104(4):745-50. doi: 10.1097/01.AOG.0000139517.26003.fc.


Objective: To compare specimens obtained with the Fischer cone biopsy excisor or loop electrosurgical excision procedure (LEEP) with respect to number of specimens obtained, margin interpretability, adequacy of excision, and ease of use.

Methods: One hundred eligible patients aged 13 years and older were randomly assigned to treatment with the Fischer cone biopsy excisor or LEEP. Eligibility criteria included: (1) cervical intraepithelial neoplasia (CIN) 2 or 3, (2) persistent CIN 1, or (3) cytologic/histologic discrepancy. Following excision, providers ranked ease of use on a scale of 1 to 10. A pathologist blinded to procedure type analyzed specimens for margin interpretability and adequacy of excision. Before study initiation we calculated that a total of 100 patients would be required to demonstrate a significant difference in the interpretable margin rate of 80% for LEEP and 99% for cone biopsy excisor (power 80%, alpha =.05).

Results: After adjustment for ease of use, lesion size, and degree of neoplasia, the cone biopsy excisor was no more likely to result in a single specimen than LEEP (74% versus 63%, relative risk [RR] 0.93, 95% confidence interval [CI] 0.79 -1.11), to result in a specimen with interpretable margins (65% versus 73%, RR 0.97, 95% CI 0.78-1.22), or to result in a fully excised cervical lesion (72% versus 62% for LEEPs, RR 1.08, 95% CI 0.77-1.52). Providers found their experiences with both Fischer cone biopsy excisor and LEEP cone biopsies to be similar, even after adjustment for year of training and previous experience (RR 0.95, 95% CI 0.72-1.24).

Conclusion: The Fischer cone biopsy excisor and LEEP performed similarly with respect to the number of final specimens, margin interpretability, and ease of use.

Level of evidence: I

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adolescent
  • Adult
  • Cervical Intraepithelial Neoplasia / pathology*
  • Conization / methods*
  • Double-Blind Method
  • Electrosurgery / methods*
  • Female
  • Humans
  • Neoplasm Staging
  • Treatment Outcome
  • Uterine Cervical Neoplasms / pathology*