Background
Phase III, open-label RCT (GHSG HD17). 1,100 patients with newly diagnosed early-stage unfavorable classical Hodgkin lymphoma. All patients received 2+2 induction chemotherapy (2×BEACOPPesc + 2×ABVD) followed by PET (PET4). Approximately 78% achieved PET4-negativity (Deauville ≤2) and were randomized; PET4-positive patients received 30 Gy RT as standard consolidation off-protocol.
Interventions and follow up
Arm A: Standard combined modality therapy (CMT): 30 Gy involved-field or involved-node RT after 2+2 chemotherapy
Arm B: PET4-guided consolidation: RT omitted if PET4-negative (Deauville ≤2); RT given only if PET4-positive
Primary endpoint: PFS; noninferiority margin 8 percentage points
Median follow up: 46.2 months
Arm B: PET4-guided consolidation: RT omitted if PET4-negative (Deauville ≤2); RT given only if PET4-positive
Primary endpoint: PFS; noninferiority margin 8 percentage points
Median follow up: 46.2 months
Results
5-yr PFS (CMT vs. PET4-guided): 97.3% (95% CI 94.5–98.7) vs. 95.1% (95% CI 92.0–97.0), HR 0.523 (95% CI 0.226–1.211); absolute difference 2.2 pp — noninferiority margin met
5-yr OS: ~99% both arms — no significant difference
ISRT vs. IF-RT subanalysis (Rosenbrock, IJROBP 2024): acute grade ≥3 toxicity 2.6% (ISRT) vs. 8.5% (IF-RT), P=.03 — ISRT equally effective and significantly less toxic
5-yr OS: ~99% both arms — no significant difference
ISRT vs. IF-RT subanalysis (Rosenbrock, IJROBP 2024): acute grade ≥3 toxicity 2.6% (ISRT) vs. 8.5% (IF-RT), P=.03 — ISRT equally effective and significantly less toxic
Adverse events
Hematologic (2+2 induction): grade ≥3 leukopenia ~70%
Gastrointestinal: grade ≥3 nausea ~30%; alopecia universal
Radiation: acute RT toxicities lower with ISRT vs. IF-RT
Late/gonadal: infertility risk from BEACOPPesc; long-term gonadotoxicity not yet fully quantified; no significant difference in late toxicity at median 46-month follow-up
Gastrointestinal: grade ≥3 nausea ~30%; alopecia universal
Radiation: acute RT toxicities lower with ISRT vs. IF-RT
Late/gonadal: infertility risk from BEACOPPesc; long-term gonadotoxicity not yet fully quantified; no significant difference in late toxicity at median 46-month follow-up
Conclusions
PET4-guided omission of RT after 2+2 induction chemotherapy met noninferiority criteria for 5-year PFS in early-stage unfavorable cHL, representing the first RCT demonstrating safe RT omission in this setting. For PET4-negative patients receiving intensive 2+2 induction, consolidation RT can be safely omitted, reducing treatment burden.
Key Limitations
Median follow-up of 46.2 months is relatively short for a disease where late relapses occur; confidence intervals on the HR are wide (0.226–1.211), reflecting the small number of events. Noninferiority applies specifically after BEACOPPesc-based induction — not after ABVD — limiting generalizability to the majority of US patients treated with ABVD. The 2.2 pp absolute difference numerically favors CMT, even if within the margin. Chemotherapy toxicity from 2+2 is not reduced — only RT is omitted. Longer follow-up to assess differential late relapse rates is needed.
Clinical Context
HD17 established the first evidence base for RT omission in early-stage unfavorable cHL after 2+2 induction, incorporated into GHSG and ESMO guidelines for centers using BEACOPPesc. The secondary ISRT analysis has driven international adoption of ISRT over IF-RT as the standard RT field. Combined with HD14, these trials define the current GHSG approach: 2+2 chemotherapy followed by RT omission in PET4-negative patients. In the US, ABVD + ISRT remains a preferred standard, with BEACOPPesc-based de-escalation as an alternative option.