title: Thymidine labeling index analysis in early breast cancer patients randomized to receive perioperative chemotherapy.
abstract: OBJECTIVE
  To identify through a substudy of a larger, multicenter study of adjuvant treatment in primary operable breast cancer patients any possible correlation between cellular proliferation rate, measured by thymidine labeling index (TLI), and perioperative chemotherapy (periCT).
  
  
  METHODS
  TLI was measured in slices of early breast carcinoma patients. The main trial was designed to randomize patients after primary surgery to receive one cycle of periCT consisting of cyclophosphamide, epidoxorubicin and 5-fluorouracil, or no periCT.
  
  
  RESULTS
  Of 600 patients randomized into the main study, 197 were eligible for inclusion in this substudy. Characteristics of patients were quite similar to those of the entire population entered into the main study. The TLI cutoff value in our series was 0.7% expressed as the median percentage ratio of thymidine-labeled cells undergoing DNA synthesis in the tumor cell population of specimens from the 197 patients. No differences were observed in terms of relapse-free survival (RFS) and overall survival (OS) after grouping the patients by TLI value (low and high) and by treatment. Among node-negative patients, a significant improvement in terms of OS (p = 0.02), but not RFS (p = 0.06), was seen in patients with a high-TLI value who underwent periCT versus controls.
  
  
  CONCLUSIONS
  TLI may be a useful tool for the identification of node-negative patients with high-TLI values who may benefit from periCT.
authors.affiliation: Department of Medical Oncology, Ospedale S. Andrea, La Spezia, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Pronzato
authors.forename: P
authors.initials: P
authors.lastname: Queirolo
authors.forename: S
authors.initials: S
authors.lastname: Vecchio
authors.forename: R
authors.initials: R
authors.lastname: Lionetto
authors.forename: L
authors.initials: L
authors.lastname: Del Mastro
authors.forename: M
authors.initials: M
authors.lastname: Venturini
authors.forename: G
authors.initials: G
authors.lastname: Gardin
authors.forename: A
authors.initials: A
authors.lastname: Alama
authors.forename: M R
authors.initials: MR
authors.lastname: Sertoli
mesh_terms: D000328:Adult; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000188:drug therapy* / Q000473:pathology / Q000601:surgery; D017024:Chemotherapy, Adjuvant; D005260:Female; D006801:Humans; D008875:Middle Aged; D016032:Randomized Controlled Trials as Topic; D012306:Risk; D012307:Risk Factors; D016019:Survival Analysis; D013936:Thymidine
chemical_list: D013936:Thymidine