title: The effect of chemotherapy against micrometastases and isolated tumor cells in lymph nodes: an in vivo study.
abstract: BACKGROUND
  The effect of perioperative chemotherapy against micrometastasis has not been elucidated. An in vivo model was established in which a gastric cancer cell line, GCIY-EGFP, metastasizes spontaneously to the lymph nodes when inoculated subcutaneously.
  
  
  METHODS
  After induction of the primary tumor by inoculation of 5 x 10(6) GCIY-EGFP cells into the lower abdominal wall of KSN nude mice, preoperative treatment with S-1 and docetaxel, or postoperative treatment with S-1 was given in addition to resection of the primary tumor to assess the efficacy of chemotherapy on isolated tumor cells (ITC) and micrometastases in the lymph nodes.
  
  
  RESULTS
  Resection of the primary tumor led to spontaneous regression of ITC but not of micrometastases. Chemotherapy delivered at 3 weeks after the inoculation of tumor cells, whether before or after surgery, was effective against micrometastasis and reduced the risk of recurrence in the lymph nodes, although not as effective against the primary tumor. Once failed to be eradicated, nodal disease grew swiftly after cessation of the chemotherapy.
  
  
  CONCLUSIONS
  ITC and micrometastases in the lymph nodes are vulnerable to chemotherapy. When objective response is achieved in a neoadjuvant setting, one may not need fear the risk of systemic disease spread during the course of the treatment.
authors.affiliation: Department of Surgery II, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya 466-8550, Japan.
authors.forename: Takehiko
authors.initials: T
authors.lastname: Eguchi
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Kodera
authors.forename: Hayao
authors.initials: H
authors.lastname: Nakanishi
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Yokoyama
authors.forename: Norifumi
authors.initials: N
authors.lastname: Ohashi
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Ito
authors.forename: Goro
authors.initials: G
authors.lastname: Nakayama
authors.forename: Masahiko
authors.initials: M
authors.lastname: Koike
authors.forename: Michitaka
authors.initials: M
authors.lastname: Fujiwara
authors.forename: Akimasa
authors.initials: A
authors.lastname: Nakao
mesh_terms: D000818:Animals; D000964:Antimetabolites, Antineoplastic / Q000627:therapeutic use*; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D045744:Cell Line, Tumor; D000077143:Docetaxel; D004338:Drug Combinations; D006801:Humans; D008207:Lymphatic Metastasis / Q000473:pathology / Q000517:prevention & control*; D008297:Male; D051379:Mice; D008819:Mice, Nude; D009362:Neoplasm Metastasis / Q000473:pathology / Q000517:prevention & control*; D010094:Oxonic Acid / Q000627:therapeutic use*; D013274:Stomach Neoplasms / Q000473:pathology*; D043823:Taxoids / Q000627:therapeutic use*; D005641:Tegafur / Q000627:therapeutic use*
chemical_list: D000964:Antimetabolites, Antineoplastic; D000970:Antineoplastic Agents; D004338:Drug Combinations; D043823:Taxoids; C079198:S 1 (combination); D005641:Tegafur; D000077143:Docetaxel; D010094:Oxonic Acid