Prognostic value and clinicopathological correlation of tumor location in gastrointestinal stromal tumor (GIST) after surgery: A propensity matched retrospective cohort study with development of a survival nomogram

Abstract

Background: There is controversy over whether tumor location affects the prognosis of GIST. The objective of this study is to compare the clinicopathological features and overall survival (OS) rates of gastrointestinal stromal tumors (GISTs) in the stomach and small bowel, as well as to identify independent prognostic factors and predict OS for GIST. Methods: A total of 504 patients who underwent surgical treatment for GIST between 2005 and 2020 were included in this retrospective cohort study. The OS of patients with small bowel GIST was compared to those with gastric GIST using Cox regression analyses and propensity score matching (PSM) techniques. Furthermore, a nomogram was developed based on significant risk factors identified through multivariate Cox analysis. The performance of the nomogram was evaluated using the area under the receiver operating characteristic (ROC) curves and calibration curves. Results: Among the entire cohort, 308 patients (61.1%) had a primary tumor located in the stomach, 129 patients (25.6%) in the duodenum, 21 patients (4.2%) in the colorectum, and 46 patients (9.1%) in other sites. Small bowel GISTs exhibited larger tumor size, higher mitotic count, higher risk stratification, and higher rates of recurrence or metastasis compared to gastric GISTs. After adjusting for potential confounders using PSM, multivariate analyses revealed that the OS of patients with small bowel GIST [hazard ratio (HR) 3.735, 95% confidence interval (CI) 1.279-10.908] was significantly shorter than that of patients with gastric GIST. Subsequently, a nomogram incorporating four prognostic risk factors, namely gender, tumor location, mitotic count, and drug therapy, was constructed to predict the 3-, 5-, and 10-year OS. The nomogram demonstrated good discriminative ability, as indicated by the area under the curve (AUC) values of 0.734, 0.849, and 0.823, respectively. Conclusions: GIST patients with tumors located in the small bowel exhibit more aggressive pathological features. Importantly, patients with small bowel GIST experience inferior survival outcomes compared to those with gastric GIST, even after adjusting for relevant risk factors through multivariate analysis and PSM. Furthermore, we successfully developed a robust nomogram which demonstrated excellent predictive accuracy for estimating long-term OS probability among GIST patients who underwent surgical intervention.