The Clinicopathologic Features and Outcome of Patients with Gastrointestinal Stromal Tumors in Colorectal Region

Abstract

Background: Gastrointestinal stromal tumor (GIST), originated from c-kit mutation, is a rare tumor in colorectal region. This study was to describe the clinicopathologic features and outcome of patients with colorectal GIST.Methods: We prospectively recorded the clinical data of colorectal tumors receiving operations in Taipei-Veterans General Hospital since 1997. The patients with the diagnosis of GIST were reviewed for the clinical courses and pathological results. The diagnosis of GIST was confirmed by positive staining of CD117 in immunohistochemistry.Results: From Dec. 1997 to Oct. 2008, 19 of the 4205 patients (0.44%) were diagnosed to have GIST. The mean age was 61.3 ± 16.2 year-old (range: 23-81 year-old). Fourteen (74%) were male. Fourteen (74%) tumors located at rectum. The mean diameter of tumor was 4.0 ± 3.3 cm. The largest size of the tumor was 13 × 7 × 6 cm. Eleven tumors showed high grade mitosis. Fifteen patients received radical resection. Nine patients received imatinib treatment for high grade mitosis, large tumor size (＞ 5 cm in diameter) and intraabdominal seeding. The average follow-up period was 40.2 ± 29.8 months (range: 3-111 months). Eleven patients had high mitosis (≧ 5/50 HPF), 7 of them had recurrent disease in 56 months (median = 29.9 ± 21.7 months). For patients with low mitosis tumor, survival rate was 87.5%, better than those with high mitosis (54.6%). High risk patients had higher risk of tumor recurrence (66.7%).Conclusion: Patients with GIST who had large tumor size (tumor size ＞ 5 cm, recurrent rate 100%) or high mitosis (mitosis ≧ 5/50 HPF, recurrent rate 63.5%) in pathological analysis had higher incidence of tumor recurrence, even after radical surgical resection.