title: Immunohistochemical assessment of localization and frequency of micrometastases in lymph nodes of colorectal cancer.
abstract: OBJECTIVE
  Micrometastases are often found in regional lymph nodes of colorectal cancer (CRC). The aim of this study is to examine the extent and distribution of such lymph nodes.
  
  
  METHODS
  We immunohistochemically assessed localization and frequency of micrometastases in 878 lymph nodes from 98 patients with CRC. The anatomical position of lymph nodes was defined as level 1 to level 3 according to distance from the main tumor.
  
  
  RESULTS
  The frequency of micrometastasis increased through observation of the 4-microm-thick lymph node sections, from one to two to five slices. With five slices, micrometastasis was frequently and extensively present in 49.1, 35.7, and 53.3% patients of histologically node-negative patients, node-positive patients at level 1, and node-positive patients at level 2, respectively. We then assessed the value of the presence of micrometastasis in node-negative patients with regard to prognosis, but no significant impact was obtained. To examine the reproducibility of the results obtained with immunohistochemistry, serial sectioning (four consecutive slices at seven different levels) of lymph nodes was additionally performed in lymph nodes initially diagnosed as micrometastasis positive. Immunohistochemical detection revealed that the sectioning level highly affected the results.
  
  
  CONCLUSIONS
  Our results indicated frequent presence of micrometastasis in lymph nodes of CRC and that micrometastasis in node-negative CRC patients did not help in predicting the outcome, in part because of the limited reproducibility with immunohistochemistry.
authors.affiliation: Department of Surgery and Clinical Oncology, Graduate School of Medicine, Osaka University, Osaka, 565-0871, Japan.
authors.forename: Shingo
authors.initials: S
authors.lastname: Noura
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Yamamoto
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Miyake
authors.forename: Byung no
authors.initials: Bn
authors.lastname: Kim
authors.forename: Osamu
authors.initials: O
authors.lastname: Takayama
authors.forename: Iwao
authors.initials: I
authors.lastname: Seshimo
authors.forename: Masakazu
authors.initials: M
authors.lastname: Ikenaga
authors.forename: Masataka
authors.initials: M
authors.lastname: Ikeda
authors.forename: Mitsugu
authors.initials: M
authors.lastname: Sekimoto
authors.forename: Nariaki
authors.initials: N
authors.lastname: Matsuura
authors.forename: Morito
authors.initials: M
authors.lastname: Monden
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002454:Cell Differentiation; D017024:Chemotherapy, Adjuvant; D015179:Colorectal Neoplasms / Q000188:drug therapy / Q000473:pathology* / Q000556:secondary; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007124:Immunoenzyme Techniques; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D008867:Microtomy; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local; D011237:Predictive Value of Tests; D011379:Prognosis; D015996:Survival Rate