Prognosis viewing for nasopharyngeal carcinoma treated with intensity-modulated radiation therapy: application of nomogram and decision curve analysis

Abstract

Objective To view and evaluate the prognosis factors in patients with nasopharyngeal carcinoma (NPC) treated with intensity modulated radiation therapy using nomogram and decision curve analysis (DCA). Methods Based on a primary cohort comprising consecutive patients with newly confirmed NPC (n = 1140) treated between January 2014 and December 2015, we identified independent prognostic factors of overall survival (OS) to establish a nomogram. The model was assessed by bootstrap internal validation and external validation in an independent validation cohort of 460 patients treated between January 2013 and December 2013. The predictive accuracy and discriminative ability were measured by calibration curve, concordance index (C-index) and risk-group stratification. The clinical usefulness was assessed by DCA. Results The nomogram incorporated T-stage, N-stage, age, concurrent chemotherapy and primary tumour volume (PTV). The calibration curve presented good agreement for between the nomogram-predicted OS and the actual measured survival probability in both the primary and validation cohorts. The model showed good discrimination with a C-index of 0.741 in the primary cohort and 0.762 in the validation cohort. The survival curves of different risk-groups were separated clearly. Decision curve analysis demonstrated that the nomogram provided a higher net benefit (NB) across a wider reasonable range of threshold probabilities for predicting OS. Conclusion This study presents a predictive nomogram model with accurate prediction and independent discrimination ability compared with combination of T-stage and N-stage. The results of DCA supported the point that PTV can help improve the prognostic ability of T-stage and should be added to the TNM staging system.

Overexpression of GINS4 Is Associated With Tumor Progression and Poor Survival in Hepatocellular Carcinoma

“…NB is defined as a pivotal value that sums the benefits (true positives) and subtracts the harms (false positives) ( 37 , 39 ). It can be plotted for a range of reasonable exchange rates in a decision curve where the potential utility of each decision strategy at each threshold probability is visualized ( 40 ). In the present study, we developed DCA by “rmda” R package, thus comparing the clinical utility of nomogram model, TNM stage, and GINS4 expression level ( 41 ).…”

Development and Validation of Prognostic Nomograms Based on Gross Tumor Volume and Cervical Nodal Volume for Nasopharyngeal Carcinoma Patients With Concurrent Chemoradiotherapy

“…In other words, for predicting OS and PFS, the accurate prediction and independent discriminative ability of our nomograms are superior to the eighth edition of the TNM staging system. Currently, no prior research has definitively evaluated CNV for clinical utility, but nomograms that include GTV as a crucial prognostic factor for NPC are available (18)(19)(20)(21)(22). However, these nomograms still have some limitations.…”

“…However, these nomograms still have some limitations. First, patients with NPC in the retrospective studies accepted chemotherapy approaches that primarily incorporated IC, CCRT, AC, IC + CCRT, and CCRT + AC (18,(20)(21)(22). Different kinds of chemotherapy regimens have different correlations with prognosis.…”

“…Hence, our studies focused on patients with NPC who received two cycles chemotherapy regimens comprised of platinum-based chemotherapy in order to reduce the impact on prognosis because of the inevitable heterogeneity of chemotherapy regimens caused by the retrospective designs. Secondly, applicability of some nomograms has become outdated because they incorporate GTV and TNM stage based on the sixth or seventh editions of AJCC/UICC staging system (18)(19)(20). It is not the same to define T-stage in different editions of the AJCC/UICC staging system.…”

“…Currently, no prior research has definitively evaluated CNV for clinical utility, but nomograms that include GTV as a crucial prognostic factor for NPC are available ( 18 – 22 ). However, these nomograms still have some limitations.…”