A higher incidence of additional malignancies has been described in patients diagnosed with gastrointestinal stromal tumors (GIST). This study aimed to identify risk factors for developing additional malignancies in patients diagnosed with GIST and evaluate the impact on survival. Individuals diagnosed with GIST from 2001 to2009 were identified from the SEER database. Logistic regression was used to identify predictors of additional malignancies and Cox-proportional hazards regression used to identify predictors of survival. In the study period, 1705 cases of GIST were identified, with 181 (10.6%) patients developing additional malignancies. Colorectal cancer was the most common cancer developing within 6 months of GIST diagnosis (30%). The median time to diagnosis of a malignancy after 6 months of GIST diagnosis was 21.9 months. Older age (p < 0.0001) and extraoesophagogastric GIST (p = 0.0027) were significant prognostic factors associated with additional malignancies. The overall 5-year survival was 65%, with the presence of additional malignancies within 6 months of GIST diagnosis associated with poor overall survival (54%, HR 1.55 1.05–2.3 95% CI, p = 0.04). Predictive factors of additional malignancies in patients diagnosed with GIST are increasing age and the primary disease site. Developing additional malignancies within 6 months of GIST diagnosis is associated with poorer overall survival. Targeted surveillance may be warranted in patients diagnosed with GIST that are at high risk of developing additional malignancies.What's new?
Gastrointestinal stromal tumor (GIST) is associated with an increased incidence of additional malignancies following diagnosis. However, the risk factors for developing second cancers and their impact on survival in affected GIST patients are unknown. In this study, increased age and extraesophagogastric GIST, with primary tumors lying outside the stomach or esophagus, were found to predict the occurrence of a second cancer in GIST patients. The development of a synchronous cancer was associated with reduced survival. The findings suggest that targeted screening and intervention could benefit GIST patients who are at high risk of second cancers.