PET-Adapted First-Line Therapy With Nivolumab for Advanced Hodgkin Lymphoma

Inclusion Criteria: * Signed written informed consent prior to any study-specific procedures * Histologically confirmed classical Hodgkin lymphoma (cHL) * Newly diagnosed disease, Ann Arbor stage IIB (bulky), III, or IV * At least one measurable lesion ≥15 mm in the longest diameter (by CT) * Age between 18 and 60 years (inclusive) * ECOG performance status 0-2 * PET-CT performed at baseline * No prior chemotherapy, radiotherapy, or immunotherapy for lymphoma * Adequate organ function, including: * Serum creatinine ≤ 0.2 mmol/L * Absence of severe cardiac, pulmonary, hepatic, or renal dysfunction * Ability to comply with the study protocol and scheduled visits Exclusion Criteria: * Active hepatitis B or C infection * Positive test for HIV * Pregnancy or breastfeeding * Prior or active autoimmune disease requiring systemic therapy * Vaccination with a live vaccine within 30 days prior to first nivolumab dose * History of non-infectious pneumonitis requiring corticosteroids * Prior malignancy (except for adequately treated basal cell carcinoma or cervical carcinoma in situ) * Congestive heart failure, unstable angina, recent myocardial infarction, or severe cardiac arrhythmias * Severe renal impairment (serum creatinine \> 0.2 mmol/L), unless lymphoma-related * Severe hepatic dysfunction, unless directly related to lymphoma * Severe pneumonia with respiratory failure or hypoxemia not corrected within 2-3 days * Sepsis or hemodynamic instability * Life-threatening bleeding events (e.g., gastrointestinal or cerebral hemorrhage) * Cachexia (total serum protein \< 35 g/L), unless due to lymphoma-related liver damage * Decompensated diabetes mellitus * Any somatic or psychiatric condition that, in the investigator's judgment, precludes informed consent or study participation