Clinical practice and outcomes in advanced gastrointestinal stromal tumor: Experience from an Indian tertiary care center

BACKGROUND: Management of advanced Gastrointestinal stromal tumors (GIST) has been revolutionized with the use of Imatinib guided by mutation analysis. Data from India remains scarce. MATERIALS AND METHODS: Patients with metastatic GIST who were treated at Department of Gastro-intestinal & Hepaticopancreaticobiliary Oncology Unit at Tata Memorial Hospital, Mumbai between December, 2004 and December 2015 were included in the analysis. Clinical and radiological data was retrieved from stored medical records and charts. RESULTS: A total of 83 patients with metastatic GIST were available for analysis. Median age was 54 years with a 3:1 male predominance. Stomach was the most common site of primary with liver being the most common site of metastasis. c-Kit mutation analysis results were available for 44 patients with exon 11 mutant being the most common mutation. With a median follow up of 33 months, the 10 years estimated progression free and overall survival (OS) was 18% and 51% respectively. Overall response rate to first line imatinib was 37.6% and estimated 3 years OS to first line therapy was significantly better for Exon 11 mutated patients (p=0.016). 34 patients received second line therapy in the form of either sunitinib, pazopanib or increased dose imatinib with a clinical benefit rate of 73.5%. C-Kit mutated patients had a better median OS compared to non mutated patients. CONCLUSIONS: GIST diagnosed and treated in the Indian subcontinent appears to show improved outcomes. The importance of c-Kit mutation analysis in determining the prognosis and outcomes of patients with advanced GIST is emphasized.