The contribution of metabolic parameters of FDG PET/CT prior and during therapy of adult patients with lymphomas

Lymphomas are the most common hematological malignancies and are further distinguished in Hodgkin lymphoma (HL) and non-Hodgkin (NHL). For staging purposes and for assessing response to treatment, the Lugano classification is currently used, both for HL and NHL patients, whereas for the assessment of prognosis, several prognostic systems exist, such as the international prognostic index (IPI) and revised-IPI for diffuse large B cell lymphomas, follicular lymphoma IPI (FLIPI)-1 and 2 for follicular lymphomas, and the international prognostic score for advanced HL. The aim of this systematic review was to determine the significance of the metabolic FDG PET/CT parameters, such as metabolic tumor volume (MTV) and total lesion glycolysis (TLG), in monitoring therapeutic interventions and prognostic outcome of patients with HL and NHL. We performed a systematic search on the literature and selection of articles concerning treatment evaluation, response and survival in association with MTV and TLG in patients with lymphomas. Our review documented that in most studies, baseline MTV and TLG were predictive of treatment response, progression-free survival (PFS) and overall survival (OS) for both HL and NHL patients. There were conflicting results for the value of interim determination of MTV and TLG. Our conclusion was that combination of baseline MTV and TLG parameters with prognostic scoring systems, such as IPI, or FLIPI-1 and -2, will add additional predictive power for response and prognosis in lymphoma patients.