Gastrointestinal stromal tumors: a 7-year experience from a tertiary care hospital.

BACKGROUND: Gastrointestinal stromal tumor (GIST), now the most common mesenchymal tumor of the gastrointestinal tract (GIT), has been frequently studied, especially with regard to its successful targeted therapy using imatinib mesylate.

AIM: Our aim was to describe the clinicopathological features of a large number of cases from a tertiary care hospital in India and report on the follow-up after treatment of some of the cases, comparing them with series described in the west.

DESIGN: This is a retrospective study of cases encountered over a 7-year period (1999-2005).

RESULTS: Ninety-two cases of GIST were studied, which made up the largest group (52.8%) of mesenchymal tumors of the GIT, with smooth muscle tumors comprising 38.1%, the next large group. GISTs were almost equally prevalent in the stomach and the small intestine, unlike in most studies where stomach is the most common site. GIST may be considered as a cause of bleeding when upper and lower GI endoscopy is normal. Ninety-five percent of the GISTs were positive for CD117 (KIT), as is known. A majority of them (70.4%) were of the high-risk malignant category, unlike most studies where high-risk tumors make up 30-45%. Histologically, the majority had a pure spindle cell morphology and skenoid fibers were rare. Follow-up of 11 cases, the majority with high-risk tumor, treated with adjuvant imatinib for 6 months after surgical resection showed stable disease for periods from 2 to 5 years. However, 11 cases treated with imatinib for longer than 6 months had a poorer outcome due to recurrent, metastatic, or inoperable disease.

CONCLUSION: In our study of a large number of GISTs, which were equally prevalent in the stomach and small intestine, the majority were of the high-risk malignant category and of pure spindle cell morphology. Limited numbers had follow-up after imatinib therapy, which showed in one group treated for 6 months, after resection of high-risk GIST, stable disease for periods ranging from 2 to 5 years. Molecular studies and larger numbers are required for meaningful conclusions to be drawn.