Overall survival and margin status in resected gastric stromal tumors

Studies assessing gastrointestinal stromal tumors (GISTs) have found no survival differences based on margin status; however, small sample sizes, merged anatomic locations, and limited follow-up have been limitations. This study examined the impact of margin status on overall survival in a large national cohort of patients with resected gastric GISTs.

Data on patients with gastric GISTs were abstracted from the National Cancer Database, with data collected over a 16-year period (2004-2020). Exclusion criteria included the presence of other primary tumors, unknown patient/tumor characteristics, macroscopic residual margins, metastasis at diagnosis, and prior chemotherapy. The cohort was stratified according to tumor size. R0 is defined as microscopically negative margin, and R1 is microscopically positive margin.

After exclusions, there were 8448 patients in the analysis cohort: 8221 (97.3%) had R0 resections, and 227 (2.7%) had R1 resections. On univariate analysis, tumor size ≤5 cm (P < .001), T1 stage (P < .001), low grade (P < .001), and low mitotic index (P < .001) were associated with a decreased risk of death. Margin status (R0 vs R1) did not have an impact on survival in the combined (P = .249), ≤5 cm (P = .961), ≤3 cm (P = .595), or ≤2 cm (P = .614) cohorts. There was also no difference in the risk of death based on the resection margin, in which the hazard ratio (R1 vs R0) with a 95% confidence interval was 1.206 (.862-1.633). In multivariate analysis, the resection margin status did not affect overall survival (P = .666).

Congruent with prior studies, there was no difference in survival when comparing R0 with R1 resections in gastric GIST patients without metastasis over an extended follow-up period. These data may be helpful in assessing suitability for endoscopic resection for patients with gastric GISTs.