A Radiation-Free Approach Based on the Whole-Body-MRI Has Shown a High Level of Accuracy in the Follow up of Lymphoma Patients. a Single Center Retrospective Study

Introduction: lymphoproliferative disorders are a heterogeneous group of oncological diseases characterized by a variable prognosis and different risk of recurrence that can occur even after years from the last line of treatment. Therefore, it is mandatory to follow up all the patients in complete remission (CR) of disease. For this purpose, the most recent guidelines do not recommend the use of imaging methods that are recommended at diagnosis including multidetector computed tomography with intravenous iodinated contrast enhancement (CE-CT) and 2-[18F]-fluoro-2-deoxy-D-glucose-positron-emission tomography (18F-FDG PET- CT) because of the potential damage from ionizing radiation especially in young patients. Whole body magnetic resonance imaging with diffusion-weighted imaging (WB-MRI-DWI) is an emerging method that, without using contrast medium and ionizing radiation, can provide similar results, if not superior in some histological subtypes, to 18F-FDG PET-CT in detecting lymphomatous localizations. This method could potentially be suitable for the follow-up of lymphoma patients.

In this retrospective single center study, we aimed to assess the accuracy of WB-MRI-DWI during follow-up of lymphoma patients in terms of sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV).

Materials and methods: 191 lymphoma patients who underwent at list one WB-MRI-DWI in our center during follow-up between February 2010 and February 2022 were enrolled. Seventy-five were Hodgkin Lymphomas, 47 diffuse large B cell lymphomas (DLBCL), 33 follicular lymphomas (FL); 10 Marginal zone lymphomas, 7 primitive mediastinal B cell lymphomas (PMBCL), 6 mantle cell lymphomas, 3 Burkitt lymphomas and 10 with more rare histotypes). Twenty-seven patients have been identified as relapsed by WB-MRI-DWI.

Results: In our cohort of patients the calculated sensitivity of WB-MRI-DWI in lymphoma surveillance was 100% (95% CI: 99.4-100.0), while specificity was 98.6% (95% CI: 97.4-99.3). The positive predictive value (PPV) was 79% (95% CI: 75.9-81.9) and the negative predictive value (NPV) 100% (95% CI: 99.4-100.0).

Conclusion: despite some limitations of the whole body magnetic resonance including the possibility of poor patient compliance and the identification of some false positives (6.3% of the total), WB-MRI-DWI is an investigation with excellent sensitivity that can identify recurrence of the disease and at the same time it could eliminate the risk of ionizing radiation.

No relevant conflicts of interest to declare.