Objective: To analyze the different factors predictive of survival associated with optimal R0-cytoreduction in c-kit-positive gastrointestinal stromal tumors.
Methods: Thirty-five patients were operated on in our Oncological Surgery Department from January 2002 to February 2007 because of CD117/c-kit-positive gastrointestinal stromal tumors, and an optimal surgical cytoreduction was obtained without macroscopical residual disease. Demographic, anatomical, clinical, pathological, and immunohistochemical variables were analyzed from a specific database. Survival and multivariate analyses were developed using Kaplan-Meier and multiple Cox regression models, respectively.
Results: Five-year overall survival was 77% with a mean survival of 52 months. Risk of malignant behaviour according to Fletcher s classification and tumor size higher than 10 cm had a significantly negative influence on overall survival in the univariate analysis (p < 0.05). Proliferative Ki-67 activity higher than 50% was the only statistically significant variable in the multivariate analysis. Twenty percent of tumors recurred. Only 3 patients with metastatic disease received adjuvant treatment with imatinib mesylate, all of them with Ki-67 > 50% and currently alive.
Conclusions: The poliferative Ki-67 index could represent an excellent predictive factor for survival in patients with c-kit-positive stromal gastrointestinal tumors. Confirmation and an adequate cut-off level should be the main objectives for future prospective studies, mostly focused on the appropriate selection of optimal candidates to imatinib-mesylate-based treatment.