Background
Phase III RCT (GELA 2003-22C trial). 334 patients with non-bulky (<7 cm) limited-stage (I–II) DLBCL achieving complete metabolic response (CMR by PET) after 4–6 cycles of R-CHOP. Randomized to consolidation IFRT 40 Gy vs observation. First randomized trial in the PET-guided era to test RT omission in non-bulky limited-stage DLBCL achieving CMR. Median follow-up 56 months.
Interventions and follow up
Arm A: IFRT 40 Gy consolidation (n=167)
Arm B: Observation — no RT (n=167)
Primary endpoint: Event-free survival (EFS)
mFollow up: 56 month
Arm B: Observation — no RT (n=167)
Primary endpoint: Event-free survival (EFS)
mFollow up: 56 month
Results
5-yr EFS: 92% (RT) vs 89% (observation) — P=.18 (not significant)
5-yr OS: 96% (RT) vs 95% (observation) — P=.9 (not significant)
Locoregional recurrence: 4% (RT) vs 4% (observation) — identical
5-yr OS: 96% (RT) vs 95% (observation) — P=.9 (not significant)
Locoregional recurrence: 4% (RT) vs 4% (observation) — identical
Adverse events
Main adverse events: RT arm: grade ≥2 fatigue, esophagitis, and skin toxicities. Grade ≥3 toxicity uncommon in both arms. No significant long-term toxicity difference at this follow-up.
Conclusions
In non-bulky limited-stage DLBCL achieving CMR after R-CHOP, consolidation RT does not improve EFS or OS and can be safely omitted. PET-guided response assessment identifies patients who do not benefit from additional RT consolidation.
Key Limitations
Key Limitations: Excludes bulky (>7 cm) disease — results cannot be extrapolated to bulky DLBCL. Requires CMR by PET, limiting applicability to patients with residual FDG-avid disease after R-CHOP. RT dose (40 Gy) higher than current standard (30–36 Gy ISRT), which may over-represent RT toxicity. The 40 Gy dose is not standard of care.
Clinical Context
Lamy Blood 2018 is the key evidence against routine consolidation RT for non-bulky limited-stage DLBCL achieving PET-CMR. Current NCCN and ESMO guidelines recommend omitting RT for PET-CMR non-bulky limited-stage DLBCL, reserving ISRT for bulky disease (≥7.5 cm) or partial metabolic response after R-CHOP.
References