Integrating pretreatment 18F-FDG PET-CT parameters, peripheral blood indicators and clinical characteristics in predicting chemotherapy plus immunotherapy outcomes for de novo metastatic nasopharyngeal carcinoma.

To develop a prognostic nomogram based on pretreatment 18F-FDG PET-CT radiomics parameters, peripheral blood indicators and clinical characteristics for risk stratification in patients with de novo metastatic nasopharyngeal carcinoma (dmNPC) receiving immunochemotherapy. The eligible patients were randomly divided into training (n=183) and validation (n=79) cohorts. Least absolute shrinkage and selection operator regression was used for variable selection. Multivariate Cox regression analysis was performed to identify independent prognostic factors for progression-free survival (PFS). The predictive accuracy and discriminative ability of the nomogram were determined with a concordance index (C-index) and calibration curve. Multivariate Cox analysis suggested that total lesion glycolysis, number of metastases, Epstein-Barr virus DNA, N-stage, lactate dehydrogenase, and total bilirubin were independent predictors of PFS and were used to develop a nomogram that could classify patients into low- and high-risk groups. The C-index of the nomogram for predicting disease progression was 0.75, which was significantly higher than the C-indices of the TNM stage and EBV DNA. The patients were then stratified into low- and high-risk groups based on the calculated scores. The median PFS was significantly higher in the low-risk group than in the high-risk group. The proposed nomogram with PET-CT parameters, peripheral blood indicators and clinical characteristics resulted in accurate prognostic prediction for patients with dmNPC receiving chemotherapy plus PD-1 inhibitors and could provide risk stratification for these patients.