title: Risk Classification using the Ki-67 Labeling Index for Surgically-Treated Gastric Gastrointestinal Stromal Tumors.
abstract: OBJECTIVE
  Adjuvant treatment with imatinib mesylate (IM) improves survival of patients with a high risk of recurrence of gastrointestinal stromal tumors (GISTs). However, the optimal adjuvant treatment strategy remains unknown. Thus, this study aimed to identify patients who do not require adjuvant IM treatment using the Ki-67 labeling index (LI).
  
  
  METHODS
  The Ki-67 LI was calculated in 59 patients with gastric GISTs. A new risk classification using the Ki-67LI and tumor size was established using cut-off values determined by receiver operating characteristic analysis. This Ki-67 classification was compared with the modified Fletcher classification (MF).
  
  
  RESULTS
  The best cut-off values for the Ki-67LI and tumor size were 8.6% and 80 mm, respectively. According to the MF, 42, 10, and 7 patients were categorized as low, intermediate, and high risk, respectively, while the Ki-67 classification rated 38, 17, and 4 patients as low, intermediate, and high risk, respectively. The 7 patients classified as high risk by MF were graded high risk (4 patients) and intermediate risk (3 patients) by the Ki-67 classification. Recurrence was not observed in patients classed intermediate risk by the Ki-67 classification.
  
  
  CONCLUSIONS
  The Ki-67 classification is helpful for identifying patients for whom adjuvant IM treatment is not necessary.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Miki
authors.forename: Taiichi
authors.initials: T
authors.lastname: Kawamura
authors.forename: Norihiko
authors.initials: N
authors.lastname: Sugisawa
authors.forename: Rie
authors.initials: R
authors.lastname: Makuuchi
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakajima
authors.forename: Masanori
authors.initials: M
authors.lastname: Tokunaga
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Tanizawa
authors.forename: Etsuro
authors.initials: E
authors.lastname: Bando
authors.forename: Masanori
authors.initials: M
authors.lastname: Terashima
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000627:therapeutic use; D017024:Chemotherapy, Adjuvant; D015331:Cohort Studies; D005260:Female; D005743:Gastrectomy; D046152:Gastrointestinal Stromal Tumors / Q000145:classification / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D000068877:Imatinib Mesylate / Q000627:therapeutic use; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D008940:Mitotic Index; D009364:Neoplasm Recurrence, Local; D011379:Prognosis; D012189:Retrospective Studies; D018570:Risk Assessment; D013274:Stomach Neoplasms / Q000145:classification / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D047368:Tumor Burden
chemical_list: D000970:Antineoplastic Agents; D019394:Ki-67 Antigen; D000068877:Imatinib Mesylate