title: Potential causes of stage migration and their prognostic implications in colon cancer: a nationwide survey of specialist institutions in Japan.
abstract: OBJECTIVE
  The actual status of stage migration in colon cancer that occurs in the procedure of preparing pathological specimens of lymph nodes has not been fully investigated.
  
  
  METHODS
  A nationwide survey of specialist institutions for colon cancer treatment was conducted to clarify interinstitutional differences in processing surgical specimens. After categorizing 111 institutions on the basis of their practice of processing specimens, distribution of tumor stage and the recurrence status of 3294 colon cancer patients treated with the same level of lymphadenectomy were compared.
  
  
  RESULTS
  Patients were diagnosed with lower tumor stages in non-teaching hospitals, in hospitals where lymph nodes were retrieved by less experienced clinicians and in hospitals in which lymph nodes were retrieved with procedures that preserved the planes of surgery around the primary tumor. However, the process of sectioning and embedding lymph nodes did not affect stage distribution. The average number of lymph nodes examined per case in each institute was 19.4. Institutional number of lymph nodes examined was not associated with node positivity but it did affect the substage in Stage III for number of lymph nodes examined ≥21. In contrast, none of the factors associated with stage migration caused interinstitutional differences in the recurrence status according to the tumor stage.
  
  
  CONCLUSIONS
  Considerable variety in the processing of surgical specimens existed even within one country, which could be a cause of stage migration in colon cancer. Better awareness of the clinical impact of the lymph node retrieval process is needed; an international guideline to standardize the treatment of surgical specimens might increase the value of tumor staging.
authors.affiliation: Department of Surgery, National Defense Medical College, Saitama ueno@ndmc.ac.jp.
authors.forename: Hideki
authors.initials: H
authors.lastname: Ueno
authors.affiliation: Department of Surgery, National Defense Medical College, Saitama.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Hase
authors.affiliation: Department of Surgery, Teikyo University School of Medicine, Tokyo.
authors.forename: Yojiro
authors.initials: Y
authors.lastname: Hashiguchi
authors.affiliation: Department of Surgery, National Defense Medical College, Saitama.
authors.forename: Eiji
authors.initials: E
authors.lastname: Shinto
authors.affiliation: Department of Laboratory Medicine, National Defense Medical College, Saitama.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Shimazaki
authors.affiliation: Department of Surgery, National Defense Medical College, Saitama.
authors.forename: Junji
authors.initials: J
authors.lastname: Yamamoto
authors.affiliation: Laboratory for Mathematics, National Defense Medical College, Saitama.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Nakamura
authors.affiliation: Department of Surgery, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Sugihara
mesh_terms: D003110:Colonic Neoplasms / Q000473:pathology* / Q000601:surgery*; D006784:Hospitals, Teaching; D006801:Humans; D007564:Japan; D008197:Lymph Node Excision / Q000379:methods / Q000592:standards; D008198:Lymph Nodes / Q000473:pathology* / Q000601:surgery; D009367:Neoplasm Staging; D013048:Specimen Handling / Q000379:methods / Q000592:standards; D011795:Surveys and Questionnaires
keywords: Will Rogers phenomenon; colon cancer; lymph nodes; pathological practice; stage migration