Population-based long-term prognosis analysis of subcutaneous gastrointestinal stromal tumors

Subcutaneous gastrointestinal stromal tumors (scGISTs) are extremely rare tumors, and the analysis of their long-term prognosis remains unreported. Therefore, our objective is to analyze the long-term prognosis of patients with scGISTs using the Surveillance, Epidemiology, and End Results database.

Patients diagnosed with GISTs between 2000 and 2019 were included in the study. To handle missing data, multiple imputation techniques were employed. Kaplan-Meier analysis and Cox proportional hazards models were used to evaluate overall survival (OS) and cancer-specific survival (CSS), and subgroup analyses were conducted for various variables.

A total of 12,882 patients were enrolled, with 12,636 diagnosed with GISTs and 246 with scGISTs. In comparison to GISTs patients, scGISTs patients exhibited inferior OS [hazard ratio (HR) 1.69, 95% confidence interval (CI) 1.45-1.98, P < 0.001] and CSS (HR 2.16, 95% CI 1.78-2.61, P < 0.001). Across various subgroups, including age, sex, surgical intervention, marital status, and chemotherapy, scGISTs patients consistently demonstrated significantly poorer OS and CSS outcomes compared to GISTs patients (P < 0.05). The 1-, 3-, and 5-year OS rates for scGISTs patients were 78.4%, 60.3%, and 49.3%, respectively, with corresponding CSS rates of 83.3%, 67.8%, and 57.4%. Notably, scGISTs patients who received surgical treatment had significantly higher 5-year OS rates (62.1% vs 30.9%, P < 0.001) and CSS rates (67.8% vs 40.0%, P < 0.001) compared to those who did not undergo surgery. Multivariate Cox regression analysis identified age, surgical status, and mitotic rate as risk factors influencing OS in scGISTs patients, while surgical status and mitotic rate were identified as risk factors affecting CSS.

Compared to GISTs patients, scGIST patients exhibit a less favorable prognosis; nonetheless, surgical intervention has been demonstrated to enhance their prognosis.