Quantitative whole-body diffusion-weighted mri after one treatment cycle for aggressive non-hodgkin lymphoma is an independent prognostic factor of outcome

Abstract

Purpose: To evaluate the prognostic utility of apparent diffusion coefficient (ADC) changes at whole-body diffusion-weighted (WBDW) MRI after one treatment cycle for aggressive non-Hodgkin lymphoma (NHL) compared with response assessment at interim and end-of-treatment fluorine 18 (18F) fluorodeoxyglucose (FDG) PET/CT. Materials and Methods: This was a secondary analysis of a prospective study (ClinicalTrials.gov identifier: NCT01231269) in which participants with aggressive NHL were recruited between March 2011 and April 2015 and underwent WB-DW MRI before and after one cycle of immunochemotherapy. Volunteers were recruited for test-retest WB-DW MRI (ClinicalTrials.gov identifier: NCT01231282) to assess ADC measurement repeatability. Response assessment was based on ADC change after one treatment cycle at WB-DW MRI and Deauville criteria at 18F-FDG PET/CT. To evaluate prognostic factors of disease-free survival (DFS), Kaplan-Meier survival analysis and univariable and multivariable Cox regression were performed; intraclass correlation coefficient (ICC) and mean difference with limits of agreement were calculated to determine interand intraobserver repeatability of ADC measurements. Results: Forty-five patients (mean age, 58 years 6 17 [standard deviation]; 31 men) and nine volunteers (mean age, 22 years 6 3; seven men) were enrolled. Median DFS was 48 months (range, 2-48 months). Outcome prediction accuracy was 86.7% (39 of 45), 71.4% (30 of 42), and 73.8% (31 of 42) for WB-DW MRI and interim and end-of-treatment 18F-FDG PET/CT, respectively. WBDW MRI (hazard ratio [HR], 17.8; P,.001) and interim (HR, 5; P=.008) and end-of-treatment (HR, 4.3; P=.017) 18F-FDG PET/CT were prognostic of DFS. After multivariable analysis, WB-DW MRI remained an independent predictor of outcome (HR, 26.8; P=.002). Intra-and interobserver agreement for ADC measurements were excellent (ICC=0.85-0.99). Conclusion: Quantitative WB-DW MRI after only one cycle of immunochemotherapy predicts DFS in aggressive NHL and is noninferior to routinely performed interim and end-of-treatment 18F-FDG PET/CT.