The results of the present study will provide information on short-term safety and efficacy of a iPET and MTV-adapted therapeutic strategy, aimed to assess the feasibility and safety on immediate disease control of a standard ABVD chemotherapy without any further treatment in patients with a very low risk or treatment failure. A second very important endpoint will be the efficacy of INRT "on demand" followed by Nivolumab maintenance for one year to rescue patients failing first-line treatment and relapsing with the pattern of "limited relapse" in terms of 3-Y failure from 2 relapse (FF2R). Patients entering into the study will be also asked to participate to a long-term follow up study (beyond ten years) to assess the prevalence of late-onset cardiovascular effects and secondary tumors in the cohort of patients enrolled in the experimental and control arm of the study. An exploratory endpoint has been also added such as the role of Minimal Residual Disease (MRD) detection by cell-free DNA assay on peripheral blood samples obtained during treatment in predicting long-term disease control.

Inclusion Criteria:

• Male or female patients aged 18-60.
• Treatment-naïve, HL patients with Ann Arbor stage I or II A non-bulky disease stratified according to modified EORTC Criteria (refer to Appendix A);
• Patients must have histologically confirmed classical HL according to the current World Health Organization Classification (nodular sclerosis, mixed cellularity, lymphocytes rich, lymphocytes depleted, or classical HL NOS [not otherwise specified];
• ECOG performance status 0-2
• Hemoglobin must be > 8 gr./dL
• Absolute neutrophil count ≥ 1,000/μL
• Platelet count ≥ 100,000/μL
• Voluntary written consent to take part to the study
• Serum Creatinine < 2.0 mg/dL and/or Creatinine clearance or calculated Creatinine clearance > 40 mL/minute
• Total bilirubin must be < 2.0 x the upper limit of normal (ULN) unless known Gilbert syndrome
• ALT or AST must be < 3 x the upper limit of normal.
• Female patients: if postmenopausal for at least 1 year before enrolment or, if fertile - agreeing to practice 2 effective methods of contraception or agreeing to practice true abstinence.
• Male patients should agree to practice barrier contraception or to practice abstinence

Exclusion Criteria:

• Composite lymphoma or nodular lymphocyte-predominant Hodgkin lymphoma;
• Bulky disease (Lugano 2014 definition: single or conglomerated nodal mass with the largest diameter measuring 10 or more centimeters);
• B symptoms;
• Extra nodal site involved by disease;
• Female patients who are both lactating and breastfeeding or who have a positive serum pregnancy test during the screening period or a positive pregnancy test on Day 1 before first dose of study drug;
• Uncompensated diabetes mellitus requiring insulin therapy;
• Any serious medical or psychiatric illness that could, in the investigator's opinion, potentially interfere with the completion of treatment according to this protocol;
• Known human immunodeficiency virus (HIV) infection with a positive search for HIV antigens by immunoblot and/or circulating copies of HIV-RNA;
• Active hepatitis B with circulating copies of HBV-DNA, or active hepatitis C infection with circulating copies of HCV-RNA;
• Severely impaired, lung and renal function;
• Diagnosed or treated for another malignancy within 3 years before the first dose or previously diagnosed with another malignancy and have any evidence of residual disease. Patients with non-melanoma skin cancer or carcinoma in situ of any type are not excluded if they have undergone complete resection;
• Active autoimmune disorder in treatment with immunosuppressive drugs
• A left-ventricular ejection fraction < 50%;
• Myocardial infarction within 2 years of study entry.
• Pregnancy or lactation.