Are there any prognostic factors for small intestinal stromal tumors?

Background Stromal tumors of the digestive tract, or gastrointestinal stromal tumors (GIST), originate from an intestinal mesenchymal precursor cell. Criteria that predict the outcome of small intestinal stromal tumors (SIST) after surgical resection are not clearly established. The aim of the study was to define prognostic criteria for SIST. Methods All c-kit positive SIST treated in our center over a 10-year period were reviewed. Results Eighteen patients with SIST treated by surgical resection were included. Overall actuarial 5-year survival was 74% (median follow-up of 69 months). We developed a panel of five criteria (tumor size, mitotic rate, proliferation index, presence of necrosis, and invasion of mucosa or adjacent structures) that permitted distinction between low and high malignant potential SIST. Presence of any four of these five criteria defined a high malignant potential SIST, and was associated with disease recurrence and poor prognosis after surgical resection (P <0.01). Patients with low malignant potential SIST had a 5-year survival of 92%, compared with 0% for high malignant potential SIST (P <0.01). Conclusions This study demonstrates that a panel of morphologic factors can reliably distinguish between low and high malignant potential SIST. Although patients with low malignant potential SIST have an excellent prognosis after surgical resection, the role of adjuvant treatment for high malignant potential SIST remains to be defined.