Clinicopathologic Study of 53 Gastrointestinal Stromal Tumors in Stomach and Small Intestine

Junya Fujita, Yasuo Tsukahara, Kazuomi Kan, Shinsuke Hata, Masashi Kitada, Takashi Shimano, Takahiko Sakuma*, Masato Hanada* and Motohisa Takami**

Department of Surgery and Department of Pathology*, Toyonaka Municipal Hospital
Kashiwara Municipal Hospital**

We studied 53 cases of upper GI GIST (gastrointestinal stromal tumor) who underwent surgical resection from 1980 to 2004. The diagnosis of GIST was defined by positive immunohistochemical staining with KIT or CD34. RESULTS: We found 33 GISTs in the stomach, 5 in the duodenum, 11 in the jejunum, and 4 in the ileum. We classified GISTs in the duodenum, jejunum, and ileum as small intestinal GISTs in this study. Mean patient age was 59.7 years, with 21 men and 32 women. The mean tumor size of 53 GISTs was 7.8 cm and that of gastric GISTs 7.2 cm and small intestinal GISTs 8.9 cm (p=0.25). The population of MI (Mitotic Index) >50/HPF was 12 of 53 GISTs, 7 of 33 (21.2%) in gastric GISTs, and 5 of 20 (25%) in small intestinal GISTs. According to the risk classification evaluated with the combination of tumor size and MI, 27.3% (9/33) of gastric GISTs and 45.0% (9/20) of small intestinal GISTs were classified as high-risk malignancy. Twelve patients suffered tumor recurrence, 3 of which were gastric GISTs and 9 were intestinal GISTs. Ten-3 of the stomach and 7 of the small intestine-died of disease in 8 months to 11 years. Median observation was 38.1 months, with overall 5-year survival of the 53 patients 77.1% and 10-year survival 70.7%. Low-risk GISTs caused no recurrence or metastasis, and 10-year disease-free survival of intermediate-risk GISTs was 95.2% and that of high-risk GISTs 36.1% (p=0.01). The prognosis of small intestinal GISTs was significantly inferior to gastric GISTs; 10-year disease-free survival of gastric GIST was 84.7%, whereas intestinal GIST was 45.4% (p=0.02). Conclusions: The predicting indicators of upper GI GIST are tumor size, MI, and tumor location. Strict follow-up is mandatory for these high-risk patients even after complete resection.

Key words
gastrointestinal stromal tumor (GIST), KIT, GIST of stomach, GIST of small intestine, mitotic index

Reprint requests
Junya Fujita Department of Surgery, Toyonaka Municipal Hospital
4-14-1 Shibahara-cho, Toyonaka, 565-8565 JAPAN

Accepted
June 22, 2005

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