title: Distribution of cervical intraepithelial neoplasia on the cervix in Chinese women: pooled analysis of 19 population based screening studies.
abstract: BACKGROUND
  Controversy remains whether a pattern of cervical intraepithelial neoplasia exists on the cervix. Our study aims at determining if the prevalence of histologically proven lesions differs by cervical four-quadrant location or by 12 o'clock surface locations of diagnosis.
  
  
  METHODS
  We conducted a retrospective, histopathological study of 19 different population based cervical cancer screening studies from 1999 to 2010 by Cancer Hospital of Chinese Academy of Medical Sciences. The Institutional Review Board for human research subjects at CHCAMS approved all of the studies. During the colposcopy procedure, participant received either 4-quadrant biopsy or directed biopsy with/without endocervical curettage. Data of all samples were stratified by the methods of sampling. Kruskal-Wallis test was used to determine overall distribution of normal/CIN1, CIN2 and CIN3+ on the cervix.
  
  
  RESULTS
  In total, 53,088 cervical samples were included in distribution analysis. 66.9% samples were obtained by random biopsy, 16.1% were by directed biopsy, and 17.0% were by endocervical curettage. 95.9%of the biopsied samples were diagnosed as normal/CIN1, 2.0% were CIN2, and 2.1% were CIN3+. CIN2 and CIN3+ were most often found in quadrants 2 and 3 (χKW2=46.6540, p<0.0001) and at the 4- and 7-o'clock positions by directed biopsy (ORCIN2=2.572, 1.689, ORCIN3+=3.481, 1.678, respectively), and at the 5-, 6-, 7-, 9- and 12-o'clock positions by random biopsy. CIN3+ was least often found at the 11-o'clock position by directed biopsy (OR=0.608).
  
  
  CONCLUSIONS
  Our results suggest a predisposition of specific locations on the cervix to CIN occurrence. Quadrants 2 and 3, especially the 4- and 7-o'clock positions should be preferentially targeted during biopsy. The decision for random biopsy should be reconsidered in future studies.
authors.affiliation: Department of Cancer Epidemiology, Cancer Hospital Chinese Academy of Medical Sciences and Peking Union Medical College, 17 South Panjiayuan Lane, PO Box 2258, 100021, Beijing, China. gw_zhaoyuqian@126.com.
authors.forename: Yu-qian
authors.initials: YQ
authors.lastname: Zhao
authors.affiliation: Department of Cancer Epidemiology, Cancer Hospital Chinese Academy of Medical Sciences and Peking Union Medical College, 17 South Panjiayuan Lane, PO Box 2258, 100021, Beijing, China. reechang@gmail.com.|University of Miami Miller School of Medicine, 3303 Pinehurst Drive, Boynton Beach, FL, USA. reechang@gmail.com.
authors.forename: Irene J
authors.initials: IJ
authors.lastname: Chang
authors.affiliation: Department of Cancer Epidemiology, Cancer Hospital Chinese Academy of Medical Sciences and Peking Union Medical College, 17 South Panjiayuan Lane, PO Box 2258, 100021, Beijing, China. zhaofangh@cicams.ac.cn.
authors.forename: Fang-hui
authors.initials: FH
authors.lastname: Zhao
authors.affiliation: Department of Cancer Epidemiology, Cancer Hospital Chinese Academy of Medical Sciences and Peking Union Medical College, 17 South Panjiayuan Lane, PO Box 2258, 100021, Beijing, China. shangyinghu@cicams.ac.cn.
authors.forename: Shang-ying
authors.initials: SY
authors.lastname: Hu
authors.affiliation: Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, 27599, USA. jsssmith@email.unc.edu.
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: Smith
authors.affiliation: Department of Pathology, Cancer Hospital Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China. zx3182004@gmail.com.
authors.forename: Xun
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Gynecology, Cancer Hospital Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China. 2230350570@qq.com.
authors.forename: Shu-min
authors.initials: SM
authors.lastname: Li
authors.affiliation: Department of Gynecology, Cancer Hospital Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China. baiping2627@sina.com.
authors.forename: Ping
authors.initials: P
authors.lastname: Bai
authors.affiliation: Department of Gynecology, Cancer Hospital Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China. zwh1941@126.com.
authors.forename: Wen-hua
authors.initials: WH
authors.lastname: Zhang
authors.affiliation: Department of Cancer Epidemiology, Cancer Hospital Chinese Academy of Medical Sciences and Peking Union Medical College, 17 South Panjiayuan Lane, PO Box 2258, 100021, Beijing, China. Qiaoy@cicams.ac.cn.
authors.forename: You-lin
authors.initials: YL
authors.lastname: Qiao
mesh_terms: D000328:Adult; D000368:Aged; D001706:Biopsy; D002584:Cervix Uteri / Q000473:pathology; D003127:Colposcopy; D055088:Early Detection of Cancer; D005260:Female; D006801:Humans; D008875:Middle Aged; D011247:Pregnancy; D013048:Specimen Handling; D002583:Uterine Cervical Neoplasms / Q000175:diagnosis* / Q000453:epidemiology / Q000473:pathology; D002578:Uterine Cervical Dysplasia / Q000175:diagnosis* / Q000453:epidemiology / Q000473:pathology