Survival analysis and prognostic factors for gastrointestinal and extragastrointestinal stromal tumors: a SEER-based study

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. Less frequently, these tumors can occur outside of the gastrointestinal tract and are termed extragastrointestinal stromal tumors (EGISTs). GISTs and EGISTs share similar molecular and histopathological characteristics; however, the exact pathogenesis of EGISTs is yet to be understood. In this study, we retrospectively reviewed all GIST cases present in the Surveillance, Epidemiology, and End Results (SEER) database. A total of 18 819 patients were included in this analysis, of which 918 had EGIST. Median overall survival and cancer-specific survival (CSS) were not reached in our study. GIST patients had significantly longer CCS than EGIST patients. EGIST, male, regional disease, distant, non-Hispanic Black, age, and radiotherapy were independently associated with shorter CCS in the general population. Contrarily, surgery was a protective factor. Distant disease, increased age, and radiotherapy were independently associated with poor CCS in EGIST patients. In conclusion, surgery should remain the mainstay of treatment in GIST and EGIST patients. The neoplasm appears to be resistant to radiotherapy, and its side effects may worsen patient survival.