Randomization
DISEASE
Patients were centrally randomized 1:1 between two parallel treatment groups before starting treatment: CMT consisting of two cycles of ABVD followed by a centrally reviewed PET/CT-based staging (PET-2) and 20 Gy IF-RT or PET-2-guided treatment, with two cycles of ABVD for all patients and 20 Gy IF-RT only for those with a positive PET-2 as defined by a Deauville score (DS) ≥ 3. Randomization was stratified according to recruiting site, age (<45 vs. ≥45 years), sex, B symptoms, disease localization (supradiaphragmatic vs infradiaphragmatic), albumin level (<40 g/L vs ≥40 g/L), and presence vs. absence of initial bulk ≥5 cm in largest diameter. Patients, investigators, and central review panel were masked to treatment allocation until a central review of PET-2 was completed.