STUDY ON KI-67 IMMUNOREACTIVITY AS A PROGNOSTIC INDICATOR IN PATIENTSWITH ADVANCED GASTRIC-CANCER

Background: Cell proliferation characteristics may reflect the aggress iveness of gastric tumors and their eventual prognosis. The aim of thi s study was to evaluate whether the proliferative activities determine d by the antibody Ki-67 could be used as a prognostic predictor in pat ients affected by advanced gastric cancer. Methods: The prognostic sig nificance of proliferative activity was investigated in 56 patients wh o underwent curative gastrectomy (R0) for advanced gastric cancer usin g the monoclonal antibody Ki-67. The patients were divided into three groups according to the Ki-67 labeling index of the tumors: <10% (18 c ases), 10-40% (21 cases) and >40% (17 cases), The Cox regression model was used to evaluate the prognostic significance of the Ki-67 index c ontrolling for age, gender, histology, depth of tumor invasion and nod e metastasis, Results: There was no significant relationship between t he Ki-67 index and wall invasion (P = 0.80) or nodal status (P = 0.73) . The cumulative 3-year survival rates (95% CI) were 61.0% (35.3-79.2% ) in patients with Ki-67 index <10%, 52.4% (29.7-70.9%) with Ki-67 ind ex 10-40% and 52.9% (27.6-73.0%) with Ki-67 index >40% and the differe nces were not statistically significant (P = 0.93). Also in multivaria te analysis the proliferative activity did not independently affect su rvival (P = 0.98). An interaction between Ki-67 index and age was foun d and Ki-67 index >40% was significantly associated with a poor progno sis in patients over 68 years old (P = 0.004). Conclusion: Our study i ndicated that the proliferative activity in gastric cancer, determined with the monoclonal antibody Ki-67, does not influence the survival e xcept in elderly patients (greater than or equal to 68 years old).