The purpose of this study is to define an improvement in patients:

• To evaluate if patients resistant to the initial treatment for residual PET-positive masses after the first two courses of ABVD (PET-2 positive), can be salvaged by early shift to high-dose chemotherapy supported by stem cell rescue
• To analyse if patients achieving early complete response (PET-2 negative), can be spared the adjuvant radiotherapy on areas of initial bulky disease, at the end of the planned six courses of ABVD. To answer this question, PET-2 negative patients will be randomized between radiotherapy versus no radiotherapy at the end of ABVD therapy.

This study is composed by two phases:

1. A phase II multi-centre study evaluating in patients with advanced stage Hodgkin lymphoma the efficacy of an early salvage treatment with high-dose chemotherapy followed by stem cell transplantation in patients FDG-PET positive after two courses of ABVD (PET-2 positive).
2. A phase III randomised study comparing the efficacy of radiotherapy to the areas of initial bulky disease versus no further therapy in PET-2 negative patients in complete remission (PET-6 negative) at the end of six courses of ABVD.

Inclusion Criteria:

• Histologically confirmed Hodgkin's lymphoma of the classical type (nodular lymphocyte predominance excluded).
• Stage IIB-IV.
• Age 18-70.
• No prior therapy for Hodgkin's lymphoma
• Written informed consent.
• ECOG performance status grades 0-3 (see Appendix E).
• FDG-PET scan before the initiation of treatment.

Exclusion Criteria:

• Prior therapy for Hodgkin's lymphoma.
• Age less than 18 or more than 70.
• Other concomitant or prior malignancies, except basal cell skin carcinoma, or adequately treated carcinoma in situ of the cervix, or any cancer in complete remission for more than 5 years.
• HIV infection.
• Pregnancy or breast-feeding.
• Renal failure (creatinine ≥2 times the normal value), liver failure (AST/ALT or bilirubine ≥ 2.5 times the normal value) or heart failure (NYHA class ≥ 2 or FEV < 45%).