Whole-body Magnetic Resonance Imaging (MRI) for Staging Malignant Lymphomas

Overview

Background: The malignant lymphomas, Hodgkin´s disease (HD) and non-Hodgkin´s lymphoma (NHL), comprise approximately 5-6% of all malignancies in adults and account for 10% of childhood cancers. Once the diagnosis has been established histologically, extent of disease (staging) and response to therapy will be assessed by means of a computed tomography (CT) scan of the body. The staging at presentation is important for determining prognosis and choice of treatment. Unfortunately, CT is accompanied by a significant amount of radiation exposure which may induce second cancers. This is especially important in childhood, because rapidly dividing cells are more sensitive to radiation induced effects and children will have more years ahead in which cancerous changes might occur. New magnetic resonance imaging (MRI) techniques offer an alternative way for staging and follow-up of cancers, including the malignant lymphomas. Whole-body MRI (WB-MRI) is a radiation-free method which allows imaging of the body with excellent soft tissue contrast in a single examination. Purpose: The aim of this study is to examine if WB-MRI can replace CT in staging of patients with a malignant lymphoma. Design: This will be a multicenter, prospective, diagnostic cohort study (timeschedule: 36 months). 135 eligible patients will undergo WB-MRI on top of the protocolar imaging routinely done. Study population: Patients aged 8 years and older with a histological diagnosis of HD or NHL. Statistical analysis: The challenge of this study will be to show non-inferiority of WB-MRI compared to CT in staging malignant lymphoma. Testing of this hypothesis will be one-sided and performed using recently proposed techniques by Lui et al. Radiation-related risk assessment: A risk model will be used, based on the BEIR VII report, for modelling the late-term mortality from radiation induced tumors after exposure to ionizing radiation. Economic evaluation: Actual costs (from a societal perspective) will be determined for the two diagnostic tests. In case of clinical equivalence and similar costs or cost savings associated with MRI the latter can be considered dominant, obviating further economic evaluation. Otherwise, through modelling of expected long term health impact and associated outcomes such as quality of life and costs the incremental cost effectiveness will be evaluated.