ABSTRACT
Objective:To explore the value of nomogram based on dual-energy CT (DECT) enhanced imaging in predicting postoperative recurrence-free survival (RFS) of early-stage glottic carcinoma (EGC).Methods:The clinicopathological and DECT data of patients with EGC confirmed by pathology in the Tianjin First Central Hospital from January 2015 to July 2018 were analyzed retrospectively. A total of 178 patients were enrolled, including 162 males and 16 females, with the age from 44 to 86 (62±9) years old. According to the follow-up data, the patients were divided into recurrent group ( n=32) and non-recurrent group ( n=146). The differences of clinicopathological data and DECT iodine maps parameters between the two groups were analyzed using χ 2 test, independent-sample t test and Mann-Whitney U test. The survival related cut-off values of the quantitative data between the two groups were selected by X-tile software. The survival curve was drawn using Kaplan-Meier method, and the difference of survival rate was tested with log-rank analysis. The variables with statistical differences were included in the Cox proportional hazard model for multivariate analysis to select the independent predictors of postoperative RFS. Based on the multivariate Cox analysis, the nomogram was drawn to predict the RFS at 1, 2 and 5 years. The prediction efficiency and clinical benefit of the nomogram were evaluated by C-index, calibration curve and decision curve analysis. Results:The median follow-up time was 24.3 months, ranging from 2 to 63 months. There was a significant difference in T-stage between recurrent and non-recurrent groups (χ2=9.21, P=0.002). The prognostic cutoff values obtained by X-tile software were arterial phase standardized iodine concentration (SIC AP)=0.28 and venous phase standardized iodine concentration (SIC VP)=0.87. The results of log-rank test showed that there were significant differences in RFS among patients with different T-stage, SIC AP and SIC VP (χ2=10.74, 15.50, 17.97, P=0.001,<0.001,<0.001). T-stage, SIC AP and SIC VP were identified as independent predictors of postoperative RFS (hazard ratio=2.271, 3.552, 3.266, P=0.026,<0.001, 0.003). The C-index of the nomogram combined with DECT parameter and T-stage was 0.785, which was higher than that of T-stage alone (0.622). The calibration curve showed that there was good consistency between the actual and predicted probability of the sample. The decision curve analysis showed that the clinical benefit of the nomogram was higher than that of the T-stage alone. Conclusion:The nomogram based on preoperative clinical factors (T-stage) and DECT iodine map factors (SIC AP and SIC vp) can predict the postoperative RFS of patients with EGC.