Incidence and Survival Outcomes of Gastrointestinal Stromal Tumors.

Importance: The incidence of gastrointestinal stromal tumors (GISTs) increased after the implementation of GIST-specific histology coding in 2001, but updated data on trends and survival are lacking. Objective: To examine the evolving epidemiology of GISTs in major organ sites. Design, Setting, and Participants: This descriptive, population-based cohort study used nationally representative data from the National Cancer Institute Surveillance, Epidemiology, and End Results (SEER) Program, including the SEER-22 and SEER-17 registries. Data were from evaluated patients aged 20 years or older with GISTs diagnosed between January 1, 2000, and December 31, 2019. Analyses were last updated on October 29, 2023. Main Outcomes and Measures: Organ site-specific trends in age-standardized incidence rates and annual percent changes (APCs) in rates were estimated by race and ethnicity and, when possible, by sex, age, and primary indicator. Multivariable Cox proportional hazards regression models were used to examine racial and ethnic differences in overall and GIST-specific survival by site. Results: The SEER-22 and SEER-17 datasets contained 23 001 and 12 109 case patients with GISTs, respectively. Patients in the SEER-22 registry had a mean (SD) age of 64 (13) years and 51.3% were men. With regard to race and ethnicity, 9.7% of patients were Asian or Pacific Islander, 12.3% were Hispanic, 19.6% were non-Hispanic Black, and 57.7% were non-Hispanic White. Overall incidence rates of GISTs in the SEER-22 cohort increased substantially over time for all organ sites but the colon (APCs: esophagus, 7.3% [95% CI, 4.4% to 10.2%]; gastric, 5.1% [95% CI, 4.2% to 6.1%]; small intestine, 2.7% [95% CI, 1.8% to 3.7%]; colon, -0.2% [95% CI, -1.3% to 0.9%]; and rectum, 1.9% [95% CI, 0.1% to 3.8%]). There were similar increasing trends by age groups (<50 vs ≥50 years), sex, race and ethnicity, and primary indicator for gastric and small intestine GISTs. Increases were mainly restricted to localized stage disease. Patients in the SEER-17 cohort had a mean (SD) age of 64 (14) years and 51.9% were men. With regard to race and ethnicity, 13.3% of patients were Asian or Pacific Islander, 11.6% were Hispanic, 17.8% were non-Hispanic Black, and 56.6% were non-Hispanic White. Non-Hispanic Black individuals had higher overall mortality for esophageal (adjusted hazard ratio [HR], 6.4 [95% CI, 2.0 to 20.3]) and gastric (adjusted HR, 1.4 [95% CI, 1.2 to 1.5]) GISTs compared with non-Hispanic White individuals. Asian or Pacific Islander individuals also had higher overall mortality for esophageal GISTs (adjusted HR, 5.6 [95% CI, 1.5 to 20.2]). Results were similar for GIST-specific survival. Conclusions and Relevance: In this cohort study using SEER data, the incidence of GISTs in major organ sites increased in the last 2 decades among several population groups. These findings suggest that additional studies are warranted to identify risk factors, because histologic reclassification and higher availability of endoscopy and imaging do not fully explain these unfavorable incidence trends. Prevention efforts are needed to reduce the substantial survival disparities among racial and ethnic minoritized populations.