The 10 Years of Experiences with GISTs

ABSTRACT

PURPOSE: Gastrointestinal stromal tumors (GISTs) possess highly variable clinical behaviors and the study thereof is insufficient. There are no standard guidelines for diagnosis and treatment of GISTs, so it is difficult to predict recurrences and conduct appropriate treatments. Throughout the last 10 years of experiences with GIST patients, we have identified the variables predicting recurrences and classified the risk groups by NIH classification, Fletcher risk stratification and UICC TNM stage. METHODS: From January 1998 to December 2007, 88 patients with pathologic confirm and surgical resection were diagnosed with GISTs. GISTs were diagnosed when the tumor had characteristic histologic features and confirmed positive by KIT, CD34, or PDGFRA. RESULTS: The size, mitotic index, existence of symptoms, and origins of tumor correlate statistically with recurrence (0.002, <0.001, 0.027, 0.011). The NIH classification, Fletcher risk stratification and UICC TNM stage are correlated with recurrence (0.001, <0.001, <0.001) and 5 year disease free survival, statistically (0.009, <0.001, <0.001). Fifteen patients experienced recurrences. 14 patients were treated with imatinib, and 6 of them showed a response to the treatment. All 4 patients who had R1 resection did not survived due to the progression of the disease. CONCLUSION: The patients with large, high mitotic index, symptomatic, or extra-gastric tumor require strict surveillance. Also, patients with low risk must be under surveillance due to the possibility of recurrence. It is important to perform R0, en bloc resection. Although the imatinib is the treatment of choice with recurred or metastatic GISTs, the disease is likely to develop resistance, further studies on newly targeted therapy is in need.