Numerical, dimensional or mixed progression disease to imatinib as prognostic factor in patients with metastatic GIST.

11040 Background: The majority of GIST patients with advanced disease initially achieves disease control from imatinib treatment. Approximately 10% of patients progresses within 6 months of starting therapy (primary resistance) and also 50-60% of the responding patients develops progression disease within two years (secondary resistance). Progression disease (PD) can be numerical, dimensional or mixed. The known prognostic factors of risk stratification in local disease are tumor size, mitotic activity and anatomic site. In this retrospective analysis we explore several clinical factors affecting survival in metastatic setting. Methods: The population included in this large database of 128…