Abstract:

Objective: The biological behavior of gastrointestinal stromal tumors (GISTs) varies widely and it is diffucult to predict their malignant potential with the current risk classification criterias. Therefore, we aimed to analyse the prognostic importance of Ki-67 LI for estimating survival outcomes in patients with GISTs. Methods: For the last 11 years, between 2006 and 2017, who had been treated after surgery were included. A single pathologist re-defined the histologic examples of all cases retrospectively. Results: Totally, 104 patients were included in the study. The median follow-up time was 73 months (range; 6 to 148 months). Seven of the 104 patients (7%) had local recurrence, 26 of the 104 patients (25%) had distant metastases and 11 of the 104 patients (11%) died during the follow-up period. The mean OS was 133 (range; 124 to 141) and the mean DFS was 117 (range; 107 to 127) months for patients. The disease progression or recurrence during follow up and increasing age were the significant prognostic factors for OS. Mitotic count, growth pattern, tumor location and Ki-67 LI were the significant prognostic factors for DFS. According to multivariate analyses, the Ki-67 LI was the only prognostic factor for estimating disease progression or recurrence (p=0.04). Conclusion: The most important prognostic factors that affect OS were the age and disease progression or recurrence of disease. Ki-67 LI was the only prognostic factor for estimating disease progression or recurrence. As the follow-up period increases, we think that Ki-67 LI also will affect overall survival.