Gastrointestinal Stromal Tumor: Clinicopathological Features, Management, and Comparison of Three Risk Stratification Schemes

Background: Gastrointestinal stromal tumor (GIST) is the most common mesenchymal neoplasm of the gastrointestinal tract. To optimize its management, different risk stratification schemes had been developed for GIST. Aim: To describe the clinicopathological profile and management of GIST and to evaluate three different GIST risk stratification schemes. Methods: Retrospective review of patients treated in a single Egyptian center during an 11-year period. High-risk GIST was identified using three different risk stratification schemes; the Armed Forces Institute of Pathology (AFIP) scheme, the National Institute of Health (NIH) consensus scheme and the American Joint Committee on Cancer (AJCC) TNM staging system. Results: The disease extent at the presentation of 34 patients was localized in 19 (56%), locally advanced in 4 (12%) and metastatic in 11 (32%). Twenty-one (62%) underwent surgery and achieved complete remission. Their median overall survival was not reached. The median disease-free survival (DFS) was 58.2 months (95%CI: 28.8 – 58.2) and the 3-year rate was 66%. Non-gastric GIST, larger tumors (>10cm) and high mitotic index (>5 / 50 HPF) was associated with shorter DFS (p = 0.146, 0.047 and 0.06, respectively). The AFIP, NIH consensus and AJCC TNM risk stratification methods identified high-risk groups that had a significantly shorter median DFS than lower-risk groups (p = 0.022, 0.009 and 0.22, respectively). Conclusion: All the studied three risk stratification schemes categorized a high-risk group with significantly poorer outcome. According to the information available, any of these schemes may be used in identifying high-risk GIST.