Navigating risk stratification systems for the management of patients with GIST

The central drivers of the aberrant behavior of gastrointestinal stromal tumors (GIST) are constitutively activated forms of stem-cell receptor factor, and, to a lesser extent, platelet-derived growth factor receptor alpha. Standard treatment for primary, localized GIST is surgical resection. Risk stratification systems assist in determining the risk of disease recurrence in individual patients with GIST, so disease management can be personalized.

In May 2010, a literature review of the PubMed database was conducted to identify articles pertaining to prognostic factors and risk stratification systems for GIST. Key results from these studies were analyzed.

The first widely accepted risk stratification system for GIST, the National Institutes of Health consensus classification system, stratified patients into risk groups on the basis of tumor size and mitotic index. Tumor location (i.e., stomach or intestine) was subsequently shown to have independent prognostic value and was incorporated into the Miettinen-Lasota/Armed Forces Institute of Pathology risk stratification system. Tumor size, location, and mitotic index remain the main variables used in risk stratification systems. Other variables such as tumor rupture and GIST genotype have recently been shown to have prognostic value. As an alternative to stratification into discrete groups, nomograms present risk of recurrence as percentages on a continuous scale. Improved use of existing prognostic variables and routine incorporation of additional variables (e.g., GIST genotype) will further refine risk stratification systems.

Refinement of risk stratification systems will increase the precision of these systems for predicting recurrence, which may facilitate improvements in individual disease management.