title: Investigation of laser cervical cone biopsies negative for premalignancy or malignancy.
abstract: OBJECTIVE
  To measure the rate of carbon dioxide, laser cone biopsies negative for premalignancy or malignancy and determine whether the clinical indications were appropriate or the pathology evaluations were correct.
  
  
  METHODS
  The patient charts of 95 negative cone biopsies were reviewed by one of the authors to determine the indications for the procedure. All of the slide reviews were done by two of the authors. Following a review of the cone biopsy slides, three deeper sections of the tissue blocks were examined in specimens that were still negative or equivocal for premalignancy. Thereafter, for those still negative the preconization, referral Pap tests, and colposcopic directed tissue samples were reviewed.
  
  
  RESULTS
  The overall negative rate of laser cone biopsy was 28% (95/341) and 68% (65/95) were done to investigate high-grade squamous intraepithelial lesions (HGSIL) (cervical intraepithelial neoplasia [CIN] 2,3). There were 25 false negative cone biopsy specimens because of misinterpretation of the original slides or discovery of pathology in additional sections. False positive reporting of some preconization Pap tests or tissue specimens as premalignant when none were seen on review likely resulted in 11 unnecessary conizations. The number of negative cones would thereby be reduced by 36 for a rate of 17% (59/341).
  
  
  CONCLUSIONS
  The negative rate could be reduced by 11% with routine deeper sectioning of the tissue blocks of the cone biopsy specimen and improved accuracy of pathological interpretation.
authors.affiliation: Department of Pathology, Prevention and Screening, Tom Baker Cancer Centre, Calgary, Alberta, Canada.
authors.forename: A Dee
authors.initials: AD
authors.lastname: Thompson
authors.forename: Máfaire A
authors.initials: MA
authors.lastname: Duggan
authors.forename: Jill
authors.initials: J
authors.lastname: Nation
authors.forename: Penny M A
authors.initials: PM
authors.lastname: Brasher