title: Neoadjuvant chemotherapy for patients with locally advanced gastric carcinoma: effect on tumor cell microinvolvement of regional lymph nodes.
abstract: BACKGROUND
  In a previous study the authors demonstrated, using immunohistochemical methods for epithelial antigens, that the regional lymph nodes of gastric adenocarcinoma contained individual tumor cells or small clusters of these cells (tumor cell microinvolvement [TCM]) in over 90% of cases. In the current study the authors used the same method to investigate a series of gastric adenocarcinoma cases treated with neoadjuvant chemotherapy prior to tumor resection; their aim was to determine the effect of chemotherapy on TCM in regional lymph nodes.
  
  
  METHODS
  Resection specimens from 17 patients with adenocarcinoma of the stomach, resected after neoadjuvant treatment and classified by routine histology as ypN0, were included in this study. One section from each of the 622 lymph nodes dissected from these specimens was stained by immunohistochemical methods for cytokeratins and Ber-Ep4.
  
  
  RESULTS
  Six patients (35%) and 25 of the 622 lymph nodes (4.0%) had TCM, compared with 93% of patients and 21.8% of lymph nodes in the previous study of patients treated with surgery alone. The lymph node response to chemotherapy correlated with the pathologic response of the primary tumor. Specifically, none of 5 patients with a complete or major pathologic response versus 6 of 12 (50%) patients with minor, partial, or no response had lymph node microinvolvement.
  
  
  CONCLUSIONS
  In comparison to our previous study, this study indicates that chemotherapy has a marked effect on tumor cells in regional lymph nodes and that the extent of this effect can be correlated with the degree of pathologic response of the primary tumor to chemotherapy.
authors: Department of Pathology, Klinikum rechts der Isar, Technical University of Munich, Germany.
authors: K
authors: K
authors: Becker
authors: U
authors: U
authors: Fumagalli
authors: J D
authors: JD
authors: Mueller
authors: U
authors: U
authors: Fink
authors: J R
authors: JR
authors: Siewert
authors: H
authors: H
authors: Höfler
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy* / Q000473:pathology; D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D017024:Chemotherapy, Adjuvant; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D013274:Stomach Neoplasms / Q000188:drug therapy* / Q000473:pathology / Q000601:surgery