Sarcomas of the gastrointestinal tract. Separation into favorable and unfavorable prognostic groups by mitotic count.

The authors reviewed the Massachusetts General Hospital experience with primary malignant stromal tumors of the gastrointestinal tract since 1962. Fifty-one of fifty-five lesions were leiomyosarcomas, and the most common anatomic location was the stomach (47%), followed by small intestine (24%), rectum (11%), colon (7%), duodenum (5%), and esophagus (5%). Most patients presented with gastrointestinal bleeding. There were peaks in age incidence in the fourth and sixth decades. All patients underwent surgery initially, and 40 of 55 had resections with "curative intent." Radiation therapy and chemotherapy were employed to a lesser extent, mainly in a palliative setting. The authors found that using number of mitoses per high-power field as the sole determinant of tumor grade yielded two very distinct clinical populations. Patients curatively resected with low-grade lesions had a better than 80% disease-free survival at 8 years, compared with a mean disease-free interval of only 18 months for high-grade lesions. In resectable disease, tumor grade appears to be the single most important prognostic factor. For gastric lesions there was no apparent advantage in extended resections compared with lesser resections encompassing all gross disease. Because of limited numbers of patients, no benefit could be demonstrated for adjuvant radiotherapy.