Role of interim positron emission tomography/computed tomography in assessment of lymphoma treatment response

Lymphoma is the most common primary hematological malignancy. FDG PET/CT has recently become the standard imaging modality for clinical management owing to its ability to provide precise, non-invasive anatomical and functional data. The purpose of this study was to highlight the role of 18F FDG-PET/CT in the management of lymphoma by monitoring treatment response, providing a guide for response-adapted therapy, and predicting the final therapeutic outcome. This was a prospective monocentric cohort observational study in which thirty-three patients with histopathologically proved lymphoma of different types performed FDG-PET/CT scanning several times throughout the 24-month duration of the study. Early-stage interim SUVmax of the most active lesion (both nodal and/or extra-nodal) was measured and statistically analyzed together with data of the international prognostic index parameters and score. Among the included 33 patients of lymphoma, international prognostic index parameters and score together with the early-stage interim SUVmax of the predominant nodal and extra-nodal sites showed statistical significance in predicting the initial as well as the final treatment response after 24 months. Using ROC analysis, we could obtain cutoff values of SUVmax of the predominant nodal lesion of 2.75 (AUC 72%, 95% CI 0.42–1.0) and SUVmax of the predominant extra-nodal lesion of 3 (AUC 70.8% and 95% CI 0.23–1.0); therefore, SUVmax of higher than these values was related to stable or progressive disease, and lower levels than these values were related to complete or partial metabolic response based on Deauville 5-point scale and Lugano response criteria. Early-stage interim PET-CT SUVmax of the predominant nodal and extra-nodal lesion could be a reliable parameter in predicting initial and final therapeutic outcome in lymphoma patients.