R-CHOP14 or R-CHOP21 &Consolidation PET-Oriented Radiotherapy (RT) in DLBCL Patients

Inclusion Criteria: * Histological diagnosis of DLBCL (CD20+), follicular lymphoma grade IIIB, T-cell rich large B cell lymphoma * Age 18-80 years (patients \>70 years old: FIT according to VGM evaluation). * aaIPI=1 +/- bulky and aaIPI=0 with bulky (\>7.5 cm) * ECOG-PS \< 3 unless due to lymphoma * Ventricular ejection fraction ≥ 50% * Pulmonary, renal and hepatic tests within normal range * Negative HIV and HBV tests. In case of HBcAb positive and HBsAb +/-, which is indicative of a past infection (occult carriers) the subject can be included, but antiviral prophylaxis with lamivudine must be given from the beginning of treatment until 12 months after treatment completion. Anti-HCV positive patients can be included in the absence of viral replication (HVR-RNA absent or less than 500 copies/ml. * Written informed consent * Life-expectancy \> 3 months Main Exclusion Criteria: * T-cell lymphoma * Follicular lymphoma (grade I, II, IIIA), marginal zone and mantle lymphoma * PS\> 3 (if not due to lymphoma) * Age-adjusted IPI = 0 in the absence of bulky disease * Age\> 80 and \<18 years (see inclusion criteria) * HIV positivity * significant cardiopathy