Gastrointestinal stromal tumors: a 19 year experience.

BACKGROUND Gastrointestinal stromal tumors are the most common mesenchymal neoplasms of the human gastrointestinal tract. OBJECTIVES To review our accumulated experience using surgery to treat gastrointestinal stromal tumors. METHODS We reviewed all patient charts and histological diagnoses of leiomyomas, leiomyosarcomas, leiomyoblastomas and schwannomas. Only tumors that displayed c-kit (CD117) immunopositivity were defined as GISTs. RESULTS The study group comprised 40 female and 53 male patients (age 26-89 years); 40.8% of the tumors were classified as malignant, 39.8% as benign, and 19.4% as of uncertain malignancy. Fifty-six GISTs were located in the stomach (60.2%), 29 in the small bowel (31.2%), 4 in the duodenum (4.3%), 2 in the colon (2.1%) and 2 in the rectum (2.1%). Incidental GISTs were found in 23.7% of our patients. Mean overall survival time for malignant gastric GISTs was 102.6 months (95% confidence interval 74.2-131.1) as compared to 61.4 months mean overall survival for malignant small bowel GISTs (95% CI 35.7-87) (P = 0.262). The mean disease-free survival period for patients with malignant gastric GISTs was 97.5 months (95% CI 69.7-125.2) as compared to only 49.6 months (95% CI 27.4-71.7) for patients with small bowel malignant GISTs (P = 0.041). CONCLUSIONS We found a high percentage of incidental GISTs. Gastric GISTs are more common than small bowel GISTs. Patients with malignant gastric GISTs have a significantly better prognosis than patients with malignant small bowel GISTs. A statistically significant correlation was found between age and malignant potential of the GIST.