ObjectiveTo explore the factors affecting postoperative cancer-specific survival (CSS) status in patients with gastrointestinal stromal tumor (GIST), and to establish a nomogram prediction model of postoperative CSS status in patients. MethodsThe clinical data of 5207 GIST patients after operation were enrolled from the SEER database. Patients were randomly divided into modeling group (n=3647) or validation group (n=1560) according to a ratio of 7 ∶3. The univariate and multivariate COX regression models were employed to analyze the influencing factors for postoperative CSS status in GIST patients, and a nomogram prediction model of 1-, 3-, and 5-year postoperative CSS status in GIST patients was established by using the R language software based on the results of multivariate COX regression analysis. The model performance was evaluated by using consistency index, calibration curve, receiver operating characteristic (ROC) curve. The K-fold cross-validation was used to perform internal validation, and the decision curve was employed to evaluate clinical applicability of the model. The predictive performance was compared between the nomogram prediction model and Modified National Institutes of Health (M-NIH) classification based on net reclassification improvement index, integrated discrimination improvement index, consistency index improvement, and area under the ROC curve. The X-tile software was used to determine the optimal cut-off value of the nomogram prediction model, so as to perform survival analysis by using Kaplan-Meier method after reclassifying GIST patients. ResultsThe results of multivariate COX regression analysis revealed that age, gender, tumor size, tumor location, liver metastasis status, American Joint Committee on Cancer (AJCC) stage, differentiated degree, comprehensive stage, mitotic rate, number of lymph node detection, and surgical method were the influencing factors for postoperative CSS status in GIST patients (P<0.05). The nomogram prediction model established based on these influencing factors (except for comprehensive stage) exerted medium discrimination, and favorable calibration, predictive efficiency, generalization ability. The predictive performance, clinical benefit of the nomogram prediction model were superior to M-NIH classification. GIST patients were reclassified as high-, medium-, and low-risk group when taking 184.7 points and 281.0 points as the optimal cut-off value, and in the modeling group and the validation group, there was a statistically significant difference in postoperative CSS status between the 3 subgroups (P<0.05). ConclusionAge, gender, tumor size, tumor location, liver metastasis status, AJCC stage, differentiated degree, comprehensive stage, mitotic rate, number of lymph node detection, and surgical method are the influencing factors for postoperative CSS status in GIST patients. The predictive performance of the nomogram prediction model established based on relevant influencing factors is superior to M-NIH classification, which is beneficial for clinicians preferably evaluate postoperative survival status in GIST patients, and optimize clinical decision-making during postoperative follow-up.