Gastric gastrointestinal stromal tumor: Does the newly proposed UICC TNM staging system provide better prognostic ability than the National Institutes of Health consensus criteria?

Abstract

Purpose The main limitation of the National Institutes of Health (NIH) consensus criteria is the biological and prognostic heterogeneity of tumors while the utility of the newly proposed UICC TNM staging system has not yet been validated. Our object is to compare the overall and disease-free survival (DFS) of patients with gastric gastrointestinal stromal tumors (GIST) using the UICC TNM staging system and the NIH consensus criteria and to determine the optimal risk stratification system for GIST. Methods Retrospective analysis of 164 patients who underwent operative management for primary gastric GIST between 1994 and 2004. Results The overall five-year survival rate was 89.6%. In the 149 patients who underwent an R0 resection, the five-year DFS rate was 86.3%. According to the NIH consensus criteria, the five-year survival rate after resection was 100% for patients in the very low-, low-, and intermediate-risk groups and 71.9% for patients in the high-risk group. The UICC TNM stages IA, IB, and II had the same survival rates (100%) and stage IIIA (75.0%) and stage IIIB (69.5%) showed no significant difference in survival compared to the NIH criteria, which precluded better risk stratification. The patients who were included in the high-risk group by NIH consensus criteria (>10 cm, ≤5/50 high power field) and were stage II by the UICC TNM staging system had a 100% five-year survival rate. Conclusion Using the current schemes, one system does not demonstrate superior prognostic ability over the other. However, the high-risk group (T4/low mitotic rate) and stage II patients appear to be appropriately classified. Keywords: Gastrointestinal stromal tumors, Neoplasm staging, Classification