title: Identification of appropriate cone length to avoid positive cone margin in high grade cervical intraepithelial neoplasia.
abstract: OBJECTIVE
  To identify key factors for predicting positive cone margin and appropriate cone length.
  
  
  METHODS
  We retrospectively reviewed the margin status of patients who received conization with high grade cervical intraepithelial neoplasia, along with other factors such as patient age, parity, preoperative cytology, size of disease, type of transformation zone, and cone length from patient records. Cut-off value of cone length was analyzed in women younger than 40 years old because we design conization with minimum length especially for women who wish for future pregnancy. Cut-off value of cone length was defined as length corresponds to estimated probability of positive cone margin equal to 0.1 by logistic regression analysis with variables selected by stepwise methods.
  
  
  RESULTS
  Among 300 patients, 75 patients had positive cone margin. Multivariable analysis revealed that squamous cell carcinoma at preoperative cytology (p=0.001), 2 or more quadrant disease (p=0.011), and shorter cone length (p<0.001) were risk factors for positive cone margin. Stepwise methods identified cone length and size of lesion as important variables. With this condition, cut-off value of cone length was estimated as 15 mm in single quadrant disease and 20 mm in 2 or more quadrant disease, respectively.
  
  
  CONCLUSIONS
  We identified the independent risk factors of positive cone margin and identified the cut-off value of cone length to avoid positive cone margin in women younger than 40 years old. Conization should be performed not only according to colposcopic findings including type of transformation zone but size of disease and cone length.
authors.affiliation: Department of Obstetrics and Gynecology, Kurume University School of Medicine, Kurume, Japan. kawano_kouichirou@kurume-u.ac.jp.
authors.forename: Kouichiro
authors.identifier: http://orcid.org/0000-0003-4354-4975
authors.initials: K
authors.lastname: Kawano
authors.affiliation: Department of Obstetrics and Gynecology, Kurume University School of Medicine, Kurume, Japan.
authors.forename: Naotake
authors.initials: N
authors.lastname: Tsuda
authors.affiliation: Department of Obstetrics and Gynecology, Kurume University School of Medicine, Kurume, Japan.
authors.forename: Shin
authors.initials: S
authors.lastname: Nishio
authors.affiliation: Biostatistics Center, Kurume University, Kurume, Japan.
authors.forename: Koji
authors.identifier: http://orcid.org/0000-0002-9712-1057
authors.initials: K
authors.lastname: Yonemoto
authors.affiliation: Department of Obstetrics and Gynecology, Kurume University School of Medicine, Kurume, Japan.
authors.forename: Kazuto
authors.identifier: http://orcid.org/0000-0003-0987-7960
authors.initials: K
authors.lastname: Tasaki
authors.affiliation: Department of Obstetrics and Gynecology, Kurume University School of Medicine, Kurume, Japan.
authors.forename: Rurika
authors.identifier: http://orcid.org/0000-0002-5899-3856
authors.initials: R
authors.lastname: Tasaki
authors.affiliation: Department of Obstetrics and Gynecology, Kurume University School of Medicine, Kurume, Japan.
authors.forename: Kimio
authors.initials: K
authors.lastname: Ushijima
mesh_terms: D000328:Adult; D002584:Cervix Uteri / Q000473:pathology*; D019092:Conization; D005260:Female; D006801:Humans; D008875:Middle Aged; D012189:Retrospective Studies; D002583:Uterine Cervical Neoplasms / Q000473:pathology*; D002578:Uterine Cervical Dysplasia / Q000473:pathology*
keywords: Cervical Intraepithelial Neoplasia; Conization; Logistic Models