Clinico-pathologic pattern of gastrointestinal stromal tumors (GIST) in southern India: A single-institution experience

Abstract

20531 Background: There have been major advances in understanding the behavioral pattern, pharmacological intervention, and clinical response of GIST; yet Indian data in this regard is sparse. This study analyses the clinico-pathologic features in 36 patients (21 male, 15 female) of GIST seen at our institution. Methods: GIST was defined as a mesenchymal spindle or epithelioid cell lesion arising in the GI tract with CD117 immuno-reactivity. Retrospective data from January 03 to March 06 was analyzed for age, tumor site, morphology, immuno- reactivity, prognostic factors, response to treatment (by RECIST), and recurrence or metastasis. All patients had surgery; those with residual, recurrent, or metastatic disease got imatinib till tumor progression. Results: GIST presented at a mean age of 48.2 yrs (SD 6.4, range 34–65). The mean tumor size was 13.9 cm (range 2–42). The most common site was the small intestine (ileum 8, jejunum 7, duodenum 4). 24 patients (66.7%) had localized disease at baseline. Of these, 14 had local recurrence after surgery, and were given imatinib. 5 of them are in complete remission, 4 had partial response (PR), 3 patients died, and 2 had stable disease. Most patients with recurrent GIST had a mitotic rate of >10/50hpf. 8 patients developed metastasis, and received imatinib. Of these, 2 got a PR, 3 had progressive disease and died, and 3 had stable disease. 12 patients (33.3%) had metastasis at baseline (to liver and abdominal cavity), and underwent debulking. Of these, 6 patients with stable disease are on treatment with imatinib, 3 died and 3 were lost to follow-up. Conclusions: Average age of presentation was less than in Western reports. The commonest site was the small intestine as opposed to stomach in western literature. Mitotic rate was a better prognostic factor than gross tumor size. GIST with a mixed cell morphology showed aggressive behavior. Imatinib mesylate is useful in the post-operative management of GIST. [Table: see text] No significant financial relationships to disclose.