Outcome and long term results of surgical resection for gastrointestinal stromal tumors (GIST)

BACKGROUND AND AIMS: Gastrointestinal Stromal Tumors (GIST) are rare; diagnosis and prognosis of these tumors are often complex. We present short and long term results of surgical resection for GIST at the Department of Surgery, University of Insubria, during a period of 14 years. MATERIAL AND METHODS: All patients' data, tumor characteristics, surgical procedure and survival data were analyzed retrospectively. Tumors were divided in risk classes using a new classification proposed by Fletcher, based on tumor size and number of mitosis. RESULTS: From 1987 to 2001 19 patients underwent surgical resection for GIST. Stomach was the most common site of localization. Complete resection was achieved in 78.9 % cases, while in 21.1% radical resection was not possible. The mean tumor size was 8.4 cm (1.2-30 cm): < 5 cm diameter in 11/19 cases (58%), 5-10 cm in 4/19 (21%) and > 10 cm in 4/19 (21%). Mitotic count was < 10/50 HPF in 68.5 % (13/19) and > 10/50 in 31.5 % (6/19). Using Fletcher's classification, tumors were divided in very low (8/19, 42.2 %), low (3/19, 15.8 %), intermediate (4/19, 21%) and high risk (4/19, 21%). The 5 years overall survival was 63 % and 34 % respectively with a statistically significant difference between tumors < 5cm and > 10 cm in diameter and between complete and incomplete resection. High risk tumors have a significantly shorter survival than low or very low risk. CONCLUSIONS: Our experience confirms that GIST are uncommon and aggressive cancers which prognosis is strictly related to tumor size and number of mitosis. Although significant advances on new chemotherapic regimes have been made, to date, radical surgical removal is the only chance of long term survival.