title: Prognostic and predictive value of the thymidylate synthase expression in patients with non-metastatic colorectal cancer.
abstract: OBJECTIVE
  To assess the value of thymidylate synthase (TS) expression as a predictive factor in the efficacy of adjuvant chemotherapy in colorectal cancer, as well as its independent prognostic value for survival.
  
  
  METHODS
  We studied 114 high risk colorectal carcinoma patients (high risk stage II and stage III), distributed in two treatment groups: surgery alone (61 patients) or surgery followed by 5-FU-based chemotherapy (53 patients). TS protein expression in the tumour tissue was assessed by immunohistochemistry.
  
  
  RESULTS
  In the surgery alone subgroup, overall survival (OS) at 5 years were 77.5% for the patients with low TS expression, against 57.7% for the patients with high TS expression (p=0.006). Among patients with low TS, there was no difference in OS as a result of whether adjuvant chemotherapy was carried out or not (65.8 vs 77.5%, p=0.29). Among the patients with high TS, there was a significant gain in OS in favor of chemotherapy (87.8 vs 57.7%, p=0.04). Analyzing the complete sample, TS expression was not shown as an independent prognostic factor for survival in the multivariate analysis.
  
  
  CONCLUSIONS
  The immunohistochemical TS expression may be used for selecting patients for better adjuvant chemotherapy protocols. In this sample, TS expression was not an independent prognostic factor for survival.
authors.affiliation: Department of Pelvic Surgery, Hospital do Câncer A.C. Camargo, São Paulo, Brazil. samuel.aguiar.jr@uol.com.br
authors.forename: S
authors.initials: S
authors.lastname: Aguiar
authors.forename: A
authors.initials: A
authors.lastname: Lopes
authors.forename: F A
authors.initials: FA
authors.lastname: Soares
authors.forename: B M
authors.initials: BM
authors.lastname: Rossi
authors.forename: F O
authors.initials: FO
authors.lastname: Ferreira
authors.forename: W T
authors.initials: WT
authors.lastname: Nakagawa
authors.forename: A L
authors.initials: AL
authors.lastname: Carvalho
authors.forename: W J D
authors.initials: WJ
authors.lastname: Filho
mesh_terms: D000368:Aged; D000964:Antimetabolites, Antineoplastic / Q000627:therapeutic use*; D014408:Biomarkers, Tumor / Q000032:analysis*; D017024:Chemotherapy, Adjuvant; D003110:Colonic Neoplasms / Q000188:drug therapy / Q000601:surgery*; D005260:Female; D005472:Fluorouracil / Q000627:therapeutic use*; D005500:Follow-Up Studies; D005544:Forecasting; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D011379:Prognosis; D012004:Rectal Neoplasms / Q000188:drug therapy / Q000601:surgery*; D012189:Retrospective Studies; D015996:Survival Rate; D013940:Thymidylate Synthase / Q000032:analysis* / Q000037:antagonists & inhibitors; D016896:Treatment Outcome
chemical_list: D000964:Antimetabolites, Antineoplastic; D014408:Biomarkers, Tumor; D013940:Thymidylate Synthase; D005472:Fluorouracil