title: Oncologic safety of pylorus-preserving gastrectomy in the aspect of micrometastasis in lymph nodes at stations 5 and 6.
abstract: BACKGROUND
  Pylorus-preserving gastrectomy (PPG) is a function-preserving gastrectomy for early gastric cancers (EGCs) that are preoperatively assessed as pN0 tumors and located in the middle portion of the stomach. In PPG, dissection of the lymph nodes at stations 5 and 6 is frequently incomplete, and this may be worrisome in terms of oncologic safety.
  
  
  METHODS
  We examined lymph nodes collected from stations 5 and 6 from 196 patients who had undergone conventional distal gastrectomy (CDG) for EGC located in the middle portion of the stomach and from 24 patients who had undergone PPG.
  
  
  RESULTS
  The average number of lymph nodes collected at station 5 was significantly lower with PPG than with CDG (0.08 vs. 1.32, respectively; P = 0.008). However, such a difference was not noted for station 6 nodes. The rate of macrometastasis was very low in all station 5 nodes (1 of 220, 0.45%) and station 6 nodes (1 of 220, 0.45%). Immunohistochemical analysis of cytokeratin in 109 cases of the CDG group and 21 cases of the PPG group showed that micrometastasis of single isolated tumor cell type was observed in only one station 6 lymph node of a patient who was initially diagnosed with pN0 EGC. There were no cases of micrometastasis in station 5 nodes.
  
  
  CONCLUSIONS
  The possibility of micrometastasis to station 5 and/or 6 lymph nodes may be negligible for EGC located in the middle portion of the stomach, and PPG thus might be the oncologically safe procedure when considering micrometastasis in remaining nodes in vivo at stations 5 and 6.
authors.affiliation: Department of Pathology, Korea University Guro Hospital, Korea University College of Medicine, Seoul, Korea.
authors.forename: Baek-Hui
authors.initials: BH
authors.lastname: Kim
authors.forename: Soon Won
authors.initials: SW
authors.lastname: Hong
authors.forename: Jong Won
authors.initials: JW
authors.lastname: Kim
authors.forename: Seung Ho
authors.initials: SH
authors.lastname: Choi
authors.forename: Sun Och
authors.initials: SO
authors.lastname: Yoon
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism / Q000473:pathology / Q000601:surgery*; D014408:Biomarkers, Tumor / Q000378:metabolism; D005260:Female; D005500:Follow-Up Studies; D005743:Gastrectomy; D006801:Humans; D007124:Immunoenzyme Techniques; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000378:metabolism / Q000473:pathology / Q000601:surgery*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D061206:Neoplasm Micrometastasis; D009367:Neoplasm Staging; D059351:Organ Sparing Treatments; D011379:Prognosis; D011708:Pylorus / Q000378:metabolism / Q000473:pathology / Q000601:surgery*; D013274:Stomach Neoplasms / Q000378:metabolism / Q000473:pathology / Q000601:surgery*
chemical_list: D014408:Biomarkers, Tumor