ROLE OF MAGNETIC-RESONANCE-IMAGING IN PREDICTING RELAPSE IN RESIDUAL MASSES AFTER TREATMENT OF LYMPHOMA

Purpose: This prospective study of patients treated at the Royal Marsden Hospital Lymphoma Unit was designed to evaluate the role of magnetic resonance imaging (MRI) in the assessment of residual masses evident on computed tomographic (CT) scanning following treatment of lymphoma. Patients and Methods: All patients had MRI, gallium-67 single-photon emission CT (67Ga SPECT), and erythrocyte sedimentation rate (ESR) performed within 3 months of completing therapy. Patients were monitored for 1 year posttreatment and observed for signs of relapse. Investigation results were correlated with disease status, and the sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) calculated. Time-to-relapse curves were derived and the logrank test used to determine whether patients with a positive result were more likely to have a relapse within the mass than those with a negative result. Results: Thirty-four patients were studied, 14 of whom relapsed, 11 within the area of residual mass. Overall, MRI had a high specificity (90%), PPV (71%), and NPV (75%), but poor sensitivity (45%). The results for 67Ga SPECT were similar, apart from lower sensitivity (33%). ESR had inferior performance in predicting relapse compared with the other tests. MRI was the only investigation to show statistical significance (P = . 14) in predicting relapse, and this was particularly evident in Hodgkin's lymphoma (P = .003). Combining results of 67Ga SPECT and MRI did not improve predictive power. Conclusion: These data demonstrate that MRI is a valuable tool in the setting of a residual mass after treatment, giving clinically useful prognostic information. 67Ga SPECT also has a role, but is less effective in predicting relapse than MRI.