Background and ObjectivesSeveral inflammation markers were found to have a prognostic value in cancer. We investigated the significance of preoperative white cell ratios in determining gastrointestinal stromal tumors (GISTs) outcome.MethodsClinicopathological features of patients who underwent surgery for GIST were reviewed. The following peripheral blood inflammation markers were calculated: neutrophil‐lymphocyte ratio (NLR), monocyte‐lymphocyte ratio (MLR), platelet‐lymphocyte ratio (PLR), neutrophil‐white blood cell ratio (NWR), lymphocyte‐white cell ratio (LWR), monocyte‐white cell ratio (MWR), and platelet‐white cell ratio (PWR).ResultsWe analyzed 127 patients. Three‐ and five‐year disease‐free survival (DFS) were 89.7% and 86.9%, respectively. The univariate analysis selected tumor diameter (P = 0.003), gastric location ( P = 0.024), cell type ( P = 0.024), mitosis ( P < 0.001), MLR ( P = 0.014), NLR ( P = 0.016), and PLR ( P = 0.001) as the factors associated to DFS. The independent prognostic factors for DFS were mitosis ( P = 0.001), NLR ( P = 0.015), MLR ( P = 0.015), and PLR ( P = 0.031), with MLR showing the highest statistical significance and hazard ratio (HR) value. MLR, NLR, and PLR were the only prognostic factors in the subgroup of patients with moderate to high Miettinen's risk class. A high value of MLR was associated with reduced DFS.ConclusionMLR, NLR, and PLR are independent prognostic factors for DFS in GISTs. We first demonstrated the role of MLR as a predictor of recurrence in GIST. Its inclusion into clinical management may improve the recurrence estimation.