Comparing GIST outcomes between geriatric and non-geriatric patients: A population-based analysis.

Abstract

e23513 Background: Gastrointestinal Stromal Tumors (GISTs) are the most common mesenchymal tumors of the GI tract, typically presenting as subepithelial neoplasms in the stomach with rarer occurrences in the small bowel, colorectum, & esophagus. Standard-of-care treatment includes surgical resection followed by Imatinib. It is unclear whether differences in patient outcomes exist across age groups. The Surveillance, Epidemiology, & End Results (SEER) program is an extensive cancer database which proves useful in analyzing cancer trends. This SEER analysis aims to investigate differences in GIST outcomes for patients aged > 70 versus ≤70 years. Methods: SEER*STAT version 8.4.0.1 was used to extract relevant gastrointestinal stromal sarcoma (ICD-O-3 8936/3) data for the years 2000-2019. Geriatric age was defined as > 70 years. Variables assessed include age, surgery, gender, cause-specific death, & overall survival. Statistical methods included univariate analysis using the KM survival estimate (95% confidence interval) for five-year survival and Log-Rank tests to observe statistical significance of the survival distribution. Multivariate Cox’s PH regression model was also used to estimate hazard ratio of death for geriatric patients adjusted for gender, stage, and surgery. Results: The number of patients included in this analysis within the study period was 13579, with an overall 5-year survival of 68.6% (95% CI: 67.7–69.5). Non-geriatric and geriatric patient data yielded 5-year survival rates of 77.4% (76.4%–78.3%) and 53.3% (51.7%–54.8%) respectively ( p< .0001). Cancer-specific death was 39.11% in 2000 and 3.33% in 2019. Male and female patients yielded 5-year survival rates of 73.0% (71.5%–74.4%) and 82.6% (81.2%–83.9%) in the younger group respectively ( p< .0001), while geriatric data yielded rates of 49.1% (46.8%–51.3%) and 57.3% (55.1%–59.4%) respectively ( p< .0001). With respect to no surgery and surgery, younger patient data yielded 5-year survival rates of 48.7% (45.8%–51.4%) and 83.7% (82.7%–84.7%) respectively ( p< .0001), while geriatric data yielded rates of 29.3% (26.5%–32.1%) and 62.8% (60.8%–64.6%) respectively ( p< .0001). Multivariate Cox PH regression model yielded an estimated hazard ratio of 2.56 (2.42–2.70) for geriatric patients ( p< .0001). Conclusions: Cancer-specific death has decreased since 2000, indicating an overall improvement in survival & treatment methods. Younger female patients had the highest 5-year survival rates, while older male patients yielded the lowest rates. We observed lower survival rates overall in the older group & a hazard ratio of 2.56 for geriatric patients. Surgery appeared to enhance survival rates in both the geriatric & non-geriatric groups, suggesting that surgery is an important factor in overall GIST survival regardless of age group. Large prospective studies will help define the appropriate management in geriatric patients.