title: Differences in chemosensitivity between primary and metastatic tumors in colorectal cancer.
abstract: OBJECTIVE
  We retrospectively evaluated the in vitro chemosensitivity of primary site and metastatic site tumors in colorectal cancer.
  
  
  METHODS
  Various resected tumor samples (33 from lymph nodes, 42 from liver, six from lung, and 68 primary tumors) were assessed via a collagen gel droplet-embedded culture drug sensitivity test to determine chemosensitivity to a single agent or a combination of agents.
  
  
  RESULTS
  Sensitivity to combination chemotherapy was significantly higher than that of monotherapy in the primary site group, lymph node group, and liver group. There was significant difference between chemosensitivity of primary site and that of liver metastasis in each agent (5-FU, p<0.001; SN38, p = 0.045; 5-FU/SN38, p<0.001; OHP, p = 0.037; 5-FU/OHP, p = 0.045).
  
  
  CONCLUSIONS
  Tumors showed greater in vitro chemosensitivity to combination therapy when compared with monotherapy. Further, tumors that had metastasized to the liver were more resistant to chemotherapy when compared with matched primary tumors.
authors.affiliation: Department of Surgery, Shiga University of Medical Science, Otsu, Shiga, Japan.
authors.forename: Katsushi
authors.initials: K
authors.lastname: Takebayashi
authors.forename: Eiji
authors.initials: E
authors.lastname: Mekata
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Sonoda
authors.forename: Tomoharu
authors.initials: T
authors.lastname: Shimizu
authors.forename: Hisanori
authors.initials: H
authors.lastname: Shiomi
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Naka
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Endo
authors.forename: Tohru
authors.initials: T
authors.lastname: Tani
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage*; D015179:Colorectal Neoplasms / Q000188:drug therapy / Q000473:pathology; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000188:drug therapy / Q000473:pathology / Q000556:secondary; D008175:Lung Neoplasms / Q000188:drug therapy / Q000473:pathology / Q000556:secondary; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009928:Organ Specificity / Q000187:drug effects