Pre-treatment T1rho imaging predicts long-term outcome in nasopharyngeal carcinoma

<title>Abstract</title> <p>Background Our recent head and neck cancer studies successfully applied T1rho imaging to tumour characterisation and prediction of short-term treatment response in nasopharyngeal carcinoma (NPC). This NPC study analysed primary tumour T1rho values for associations with nodal metastases and for the prediction of long-term outcome. Materials and Methods This study prospectively recruited 114 eligible patients for pre-treatment T1rho imaging of the primary NPC. The mean T1rho of primary NPCs were correlated with disease free survival (DFS), locoregional relapse free survival (LRRFS), and distant metastases free survival (DMFS) using the Cox regression analysis, and then together with other variables were added to the multivariable model to identify independent variables and a combined category was proposed. The survival rates of each group in the combined category were calculated. Results Low T1rho values correlated with high risk of N+ (p &lt; 0.001) and poor DMFS (p = 0.04), but not with DFS or LRRFS (p &gt; 0.05). T1rho and N-category were independent variables for DMFS (p &lt; 0.05). Patients with N0 in N-category, and patients in the low-risk group (combination of N0 or T1rho of&gt;70msec) from the combined category showed 100% 3-year DMFS. The low-risk group in the combined category included more patients (n = 45) than patients with N0 in N-category (n = 28). Conclusion Low T1rho values are associated with the presence of nodal metastases and prediction of poor DMFS, but not LRRFS in NPC. The use of N0 or T1rho of &gt; 70 msec potentially identifies more patients with low risk of distant metastases than that of N0 only.</p>