Pre-treatment amide proton transfer imaging predicts treatment outcome in nasopharyngeal carcinoma

Abstract

Objective: To investigate the value of pre-treatment amide proton transfer–weighted (APTw) imaging for predicting survival of patients with nasopharyngeal carcinoma (NPC). Materials and methods: Pre-treatment APTw imaging was performed in 77 NPC patients and the mean, 90th percentile, skewness, and kurtosis of APT asymmetry (APTmean, APT90, APTskewness, and APTkurtosis, respectively) were obtained from the primary tumor. Associations of APTw parameters with locoregional relapse–free survival (LRRFS), distant metastasis–free survival (DMFS), and disease-free survival (DFS) after 2 years were assessed by univariable Cox regression analysis and significant APTw parameters, together with age, sex, treatment, and stage as confounding variables, were added to the multivariable model. Kaplan-Meier analysis was used to determine the prognostic significance of patients with high or low APT values based on a threshold value from receiver operating characteristic curve analysis. Results: Locoregional relapse, distant metastases, and disease relapse occurred in 14/77 (18%), 10/77 (13%), and 20/77 (26%) patients, respectively, at a median follow-up of 48.3 (10.6–67.4) months. Univariable analysis showed significant associations of LRRFS with APTskewness (HR = 1.98; p = 0.034), DMFS with APTmean (HR = 2.44; p = 0.033), and APT90 (HR = 1.93; p = 0.009), and DFS with APTmean (HR = 2.01; p = 0.016), APT90 (HR = 1.68; p = 0.009), and APTskewness (HR = 1.85; p = 0.029). In multivariable analysis, the significant predictors for DMFS were APT90 (HR = 3.51; p = 0.004) and nodal stage (HR = 5.95; p = 0.034) and for DFS were APT90 (HR = 1.97; p = 0.010) and age (HR = 0.92; p = 0.014). An APT90 ≥ 4.38% was associated with a significantly poorer DFS at 2 years than APT90 < 4.38% (66% vs. 91%; HR = 4.01; p = 0.005). Conclusion: APTw imaging may potentially predict survival in patients with NPC. Key Points: • APTw imaging may provide new markers to predict survival in nasopharyngeal carcinoma. • APT90is an independent predictor of distant metastases–free survival and disease-free survival. • The APThighgroup is at higher risk of disease relapse than the APTlowgroup.