Objective To construct of a computed tomography (CT) based radiomics model for predicting the prognosis of patients with gastric neuroendocrine neoplasm (GNEN) and inves-tigate its application value.

Methods The retrospective cohort study was conducted. The clinico-pathological data of 182 patients with GNEN who were admitted to 2 medical centers, including the First Affiliated Hospital of Zhengzhou University of 124 cases and the Affiliated Cancer Hospital of Zhengzhou University of 58 cases, from August 2011 to December 2020 were collected. There were 130 males and 52 females, aged 64(range, 56-70)years. Based on random number table, all 182 patients were divided into the training dataset of 128 cases and the validation dataset of 54 cases with a ratio of 7:3. All patients underwent enhanced CT examination. Observation indicators: (1) construction and validation of the radiomics prediction model; (2) analysis of prognostic factors for patients with GNEN in the training dataset; (3) construction and evaluation of the prediction model for prognosis of patients with GNEN. Measurement data with skewed distribution were represented as M(range), and comparison between groups was conducted using the Mann‑Whitney U test. Count data were described as absolute numbers, and the chi‑square test, corrected chi‑square test or Fisher exact probability were used for comparison between groups. The Kaplan‑Meier method was used to calculate survival rate and draw survival curve, and the Log‑rank test was used for survival analysis. The COX regression model was used for univariate and multivariate analyses. The R software (version 4.0.3) glmnet software package was used for least absolute shrinkage and selection operator (LASSO)-COX regression analysis. The rms software (version 4.0.3) was used to generate nomogram and calibration curve. The Hmisc software (version 4.0.3) was used to calculate C‑index values. The dca.R software (version 4.0.3) was used for decision curve analysis.

Results (1) Construction and valida-tion of the radiomics prediction model. One thousand seven hundred and eighty‑one radiomics features were finally extracted from the 182 patients. Based on the feature selection using intra‑group correlation coefficient >0.75, and the reduce dimensionality using LASSO‑COX regression analysis, 14 non zero coefficient radiomics features were finally selected from the 1 781 radiomics features. The radiomics prediction model was constructed based on the radiomics score (R‑score) of these non zero coefficient radiomics features. According to the best cutoff value of the R‑score as -0.494, 128 patients in the training dataset were divided into 64 cases with high risk and 64 cases with low risk, 54 patients in the validation dataset were divided into 35 cases with high risk and 19 cases with low risk. The area under curve (AUC) of radiomics prediction model in predicting 18‑, 24‑, 30‑month overall survival rate of patients in the training dataset was 0.8395% confidence interval (CI ) as 0.76-0.87, P<0.05, 0.84(95%CI as 0.73-0.91, P<0.05), 0.91(95%CI as 0.78-0.95, P<0.05), respectively. The AUC of radiomics prediction model in predicting 18‑, 24‑, 30‑month overall survival rate of patients in the validation dataset was 0.84(95%CI as 0.75-0.92, P<0.05), 0.84 (95%CI as 0.73-0.91, P<0.05), 0.86(95%CI as 0.82-0.94, P<0.05), respectively. (2) Analysis of prognostic factors for patients with GNEN in the training dataset. Results of multivariate analysis showed gender, age, treatment method, tumor boundary, tumor T staging, tumor N staging, tumor M staging, Ki‑67 index, CD56 expression were independent factors influencing prognosis of patients with GNEN in the training dataset (P<0.05). (3) Construction and evaluation of the prediction model for prognosis of patients with GNEN. The clinical prediction model was constructed based on the independent factors influen-cing prognosis of patients with GNEN including gender, age, treatment method, tumor boundary, tumor T staging, tumor N staging, tumor M staging, Ki‑67 index, CD56 expression. The C‑index value of clinical prediction model in the training dataset and the validation dataset was 0.86 (95%CI as 0.82-0.90) and 0.80(95%CI as 0.72-0.87), respectively. The C‑index value of radiomics prediction model in the training dataset and the validation dataset was 0.80 (95%CI as 0.74-0.86, P<0.05) and 0.75(95%CI as 0.66-0.84, P<0.05), respectively. The C‑index value of clinical‑radiomics combined prediction model in the training dataset and the validation dataset was 0.88(95%CI as 0.85-0.92) and 0.83 (95%CI as 0.77-0.89), respectively. Results of calibration curve show that clinical prediction model, radiomics prediction model and clinical‑radiomics combined prediction model had good predictive ability. Results of decision curve show that the clinical‑radiomics combined prediction model is superior to the clinical prediction model, radiomics prediction model in evaluating the prognosis of patients with GNEN.

Conclusions The predection model for predicting the prognosis of patients with GNEN is constructed based on 14 radiomics features after selecting. The prediction model can predict the prognosis of patients with GNEN well, and the clinical‑radiomics combined prediction model has a better prediction efficiency.