Gastric GISTs. Personal experience

Abstract

BACKGROUND: With term GIST is now defined a group of mesenchimal tumours of the gastrointestinal tract expressing immunopositivity for kit protein kinase (CD117). Surgical therapy remains the gold standard for these rare tumours. Imatinib Mesylate (STI-571) is a potent inhibitor of Kit Kinase activity and different reports demonstrated its efficacy in unresectable or metastatic Gists. Aim of the paper: To value the incidence of GISTs among gastric mesenchimal neoplasms and analyzed their clinical presentation, prognostic parameters and surgical treatment. The response to Imatinib Mesylate in a case of metastatic GIST is then valued.

METHODS: Twelve cases of gastric mesenchimal neoplasms are retrospectively reviewed and tested by CD117 immmunopositivity identifyng 8 GISTs. The median follow-up was 37 (range7-120) months. We describe in details the case of a metastatic Gist treated for 15 months with Imatinib Mesylate.

RESULTS: The 67 per cent of mesenchimal gastric tumours were CD117+. Gastrointestinal bleeding was the most common presenting symptom. The 50% of patiens with malignant GISTS had a palpable abdominal mass at diagnosis. All tumors < 5 cm in diameter had a mitotic count (MC) <5/50 high-power fields (HPFs) except a case of high grade leiomyosarcoma. Surgical therapy was complete tumour resection with free margins.

No recurrence was observed in lesions <5cm and < 5 mitosis/50 High Power Fields(HPFs). A good response to Imatinib Mesylate was reported in a metastatic GIST.

CONCLUSION: The surgeon’s role in gastric Gist’s treatment is to achieve a complete cancer resection with free margins. In advanced lesions, even in presence of hepatic metastases, surgical resection of the mass is indicated because is possible to obtain a stabilization or a partial remission with Imatinib Mesylate palliative treatment in some patients.