Background
SEER-Medicare database analysis of limited-stage DLBCL treatment patterns and outcomes in the United States in the rituximab era. Compared patients receiving chemoimmunotherapy alone vs combined modality therapy (chemoimmunotherapy + RT). Examined real-world utilization of RT and its association with survival outcomes in older patients.
Interventions and follow up
Arm A: Chemoimmunotherapy + RT (n=approximately half of cohort)
Arm B: Chemoimmunotherapy alone (n=approximately half of cohort)
Primary endpoint: Overall survival and lymphoma-specific survival
mFollow up: Variable (SEER-Medicare)
Arm B: Chemoimmunotherapy alone (n=approximately half of cohort)
Primary endpoint: Overall survival and lymphoma-specific survival
mFollow up: Variable (SEER-Medicare)
Results
Lymphoma-specific survival: Significantly better with CMT vs chemo alone in adjusted analysis
RT utilization: Declining over time — from ~60% to ~30% of limited-stage DLBCL patients receiving RT
OS benefit of RT: HR ~0.70–0.80 favoring CMT in adjusted analyses
RT utilization: Declining over time — from ~60% to ~30% of limited-stage DLBCL patients receiving RT
OS benefit of RT: HR ~0.70–0.80 favoring CMT in adjusted analyses
Adverse events
Main adverse events: N/A (population database; toxicity not captured).
Conclusions
Real-world SEER-Medicare data suggest that consolidation RT is associated with improved lymphoma-specific survival for limited-stage DLBCL in the rituximab era, despite declining utilization of RT over time. These findings support continued use of consolidation RT for appropriate patients.
Key Limitations
Key Limitations: Database study with inherent selection and confounding bias — patients who received RT may have been healthier or have had more favorable disease. SEER-Medicare captures predominantly older patients (≥65), limiting generalizability to younger patients. Chemotherapy regimen not standardized; some patients may not have received R-CHOP.
Clinical Context
This SEER analysis is part of the conflicting evidence on consolidation RT for limited-stage DLBCL. While observational data (SEER, MDACC) generally support RT, the Lamy Blood 2018 randomized trial found no benefit in non-bulky disease. The current consensus is to limit RT to bulky disease.
References