Gastrointestinal stromal tumors (GIST) of the stomach: retrospective experience with surgical resection at the National Cancer Institute.

Background: Gastric GISTs account for more than half of all gastrointestinal stromal tumors and represent less than 5% of all gastric tumors. The peak age for harboring GIST of the stomach is around 60 years and a slight male preponderance is reported. These tumors are identified by expression of CD117 or CD34 antigen. Symptoms at presentation usually include bleeding, abdominal pain or abdominal mass. Endoscopically, they typically appear as a submucosal mass with or without ulceration and on CT scans an extragastric mass is usually seen. Complete surgical resection provides the only chance for cure, with only 1-2 cm free margins needed. However, local recurrence and/or metastases supervene in almost half the patients treated with surgery alone, even when no gross residual is left. Thereby imatinib mesylate was advocated as an adjuvant to surgery, which appears to have improved disease-free and overall survival.

Aim Of The Work: The aim of this work was to assess clinico-pathological features of gastrointestinal stromal tumors (GIST) of the stomach and to appraise the results of treatment by surgery in patients treated at the National Cancer Institute (NCI) of Cairo between January 2002 and December 2007.

Patients And Methods: Nineteen patients with histologically and immuno-histochemically proven GIST of the stomach were treated by surgery at the NCI during the 6-year study period. Preoperative assessment included detailed history, clinical examination, full laboratory tests, endoscopy, abdominal ultrasound and CT. General medical assessment included chest X-ray, ECG and echocardiography.

Results: The patients' age ranged from 26 to 77 years with a median of 51 years. Obvious male/female preponderance was noticed (68.4% to 31.6%). Tumors were located at the upper 1/3 in 42.1%, at the middle 1/3 in 31.6% and at the lower 1/3 in 26.3%. The most common clinical presentation was related to bleeding (hematemesis, melena or anaemia) and was seen in 63.2%. No tumors were labeled as very low or low risk while there were 52.6% intermediate risk and 47.4% high risk. Wedge resection was carried out in 15.8%, partial gastrectomy in 37.8%, total gastrectomy in 5.2%, extended gastric resection in 21.1% and only biopsy in 5.2%. Lymphadenectomy was carried out in 5/19 patients to reveal negative lymph nodes in all five. Complications occurred in 73.7% of patients and only 1 case of early postoperative mortality was recorded. Two patients were lost to follow-up. The remaining 16 patients were followed-up for a period ranging from 6-34 months with a mean of 19.5+/-5.6 months and they were all alive by the end of the study, 10 were free of disease and 6 showed disease recurrence.

Conclusion: Gastric GIST can present with vague and non specific clinical picture. Therefore, thorough clinical and radiological evaluation and preoperative endoscopy and biopsy are essential to reach the diagnosis and to assess the risk for metastasis. The clinical outcome of these tumors is influenced by completeness of tumor extirpation while avoiding tumor rupture, and by the tumor malignant potential. Accordingly for tumors with adverse factors, multimodal therapy with adjuvant imatinib or one of its successors should be considered in order to improve overall and disease-free survival.