title: [A systematic review of worldwide natural history models of colorectal cancer: classification, transition rate and a recommendation for developing Chinese population-specific model].
abstract: Objective:To review the worldwide studies on natural history models among colorectal cancer (CRC), and to inform building a Chinese population-specific CRC model and developing a platform for further evaluation of CRC screening and other interventions in population in China.Methods:A structured literature search process was conducted in PubMed and the target publication dates were from January 1995 to December 2014. Information about classification systems on both colorectal cancer and precancer on corresponding transition rate, were extracted and summarized. Indicators were mainly expressed by the medians and ranges of annual progression or regression rate.Results:A total of 24 studies were extracted from 1 022 studies, most were from America (n=9), but 2 from China including 1 from the mainland area, mainly based on Markov model (n=22). Classification systems for adenomas included progression risk (n=9) and the sizes of adenoma (n=13, divided into two ways) as follows: 1) Based on studies where adenoma was risk-dependent, the median annual transition rates, from ' normal status' to ' non-advanced adenoma', 'non-advanced' to ' advanced' and ' advanced adenoma' to CRC were 0.016 0 (range: 0.002 2-0.020 0), 0.020 (range: 0.002-0.177) and 0.044 (range: 0.005-0.063), respectively. 2) Median annual transition rates, based on studies where adenoma were classified by sizes, into <10 mm and ≥10 mm (n=7), from ' normal' to adenoma <10 mm, from adenoma <10 mm to adenoma ≥10 mm and adenoma ≥ 10 mm to CRC, were 0.016 7 (range: 0.015 0-0.037 0), 0.020 (range: 0.015-0.035) and 0.040 0 (range: 0.008 5-0.050 0), respectively. 3) Median annual transition rates, based on studies where adenoma, were classified by sizes into diminutive (≤5 mm), small (6-9 mm) and large adenoma (≥10 mm) (n=6), from ' normal' to diminutive adenoma,'diminutive' to ' small','small' to ' large', and large adenoma to CRC were 0.013 (range: 0.009-0.019), 0.043 (range: 0.020-0.085), 0.044 (range: 0.020-0.125) and 0.033 5 (range: 0.030-0.040), respectively. Staging system of CRC mainly included LRD (localized/regional/distant,n=10), Dukes' (n=7) and TNM (n=3). When using the LRD classification, the median annual transition rates from ' localized' to ' regional' and ' regional' to 'distant' were 0.28 (range: 0.20-0.33) and 0.40 (range: 0.24-0.63), respectively. Under the Dukes' classification, the median annual transition rates appeared as 0.583 (range: 0.050-0.910), 0.656 (range: 0.280-0.720) and 0.830 (range: 0.630-0.865) from Dukes' A to B, B to C and C to Dukes' D, respectively. Again, when using the TNM classification, very limited transition rate was reported. Serrated pathway was only described in one study.Conclusions:Studies on the natural history model of colorectal cancer was still limited worldwide. Adenoma seemed the most common status setting for precancer model, and the risk-dependent classification for adenoma was consistent with the most commonly used system in clinical practice as well as major cancer screening programs in China. Since the staging systems of cancers varied, and shortage of transition rates based on TNM classification (commonly used in China), there will be a challenge for building Chinese population-specific natural history model of colorectal cancer, information from other classification systems could be conditionally applied.
authors.affiliation: Program Office for Cancer Screening in Urban China, National Cancer Center, Cancer Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100021, China; Department of Oncology, Kai-Luan Hospital, Tangshan 063000, China.
authors.forename: Z F
authors.initials: ZF
authors.lastname: Li
authors.affiliation: Program Office for Cancer Screening in Urban China, National Cancer Center, Cancer Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100021, China.
authors.forename: H Y
authors.initials: HY
authors.lastname: Huang
authors.affiliation: Program Office for Cancer Screening in Urban China, National Cancer Center, Cancer Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100021, China.
authors.forename: J F
authors.initials: JF
authors.lastname: Shi
authors.affiliation: Abdominal Surgery, National Cancer Center, Cancer Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100021, China; Program Office for Cancer Screening in Urban China, National Cancer Center, Cancer Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100021, China.
authors.forename: C G
authors.initials: CG
authors.lastname: Guo
authors.affiliation: Department of Pathology, National Cancer Center, Cancer Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100021, China; Program Office for Cancer Screening in Urban China, National Cancer Center, Cancer Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100021, China.
authors.forename: S M
authors.initials: SM
authors.lastname: Zou
authors.affiliation: Program Office for Cancer Screening in Urban China, National Cancer Center, Cancer Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100021, China.
authors.forename: C C
authors.initials: CC
authors.lastname: Liu
authors.affiliation: Health Center for Staff, Kai-Luan Hospital, Tangshan 063000, China; Program Office for Cancer Screening in Urban China, National Cancer Center, Cancer Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100021, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Program Office for Cancer Screening in Urban China, National Cancer Center, Cancer Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100021, China.
authors.forename: L
authors.initials: L
authors.lastname: Wang
authors.affiliation: Office for Cancer Control and Research, Hunan Cancer Hospital, Changsha 410006, China; Program Office for Cancer Screening in Urban China, National Cancer Center, Cancer Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100021, China.
authors.forename: S L
authors.initials: SL
authors.lastname: Zhu
authors.affiliation: Health Center for Staff, Kai-Luan Hospital, Tangshan 063000, China.
authors.forename: S L
authors.initials: SL
authors.lastname: Wu
authors.affiliation: Program Office for Cancer Screening in Urban China, National Cancer Center, Cancer Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100021, China.
authors.forename: M
authors.initials: M
authors.lastname: Dai
mesh_terms: D000368:Aged; D002471:Cell Transformation, Neoplastic; D002681:China; D015179:Colorectal Neoplasms / Q000145:classification / Q000401:mortality / Q000473:pathology*; D003198:Computer Simulation; D018450:Disease Progression; D055088:Early Detection of Cancer; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging
keywords: Adenoma; Colorectal neoplasms; Natural history; Transition rate