Diffuse Large B-Cell LymphomaClinical Notes for Practicing Oncologists
From cell-of-origin classification and IPI/NCCN-IPI risk stratification through R-CHOP vs Pola-R-CHP first-line treatment, CNS prophylaxis, and R/R management with CAR-T and bispecific antibodies.
Pola-R-CHP 2-yr PFS
~76.7%
POLARIX, IPI 2-5
R-CHOP 2-yr PFS
~70.2%
POLARIX comparator
NCCN-IPI Low 5-yr OS
~96%
Score 0-1
CNS-IPI High Relapse
~10.2%
2-yr CNS relapse risk
How is DLBCL classified, diagnosed, and risk-stratified by cell-of-origin, genetics, and clinical prognostic indices?
DLBCL is the most common non-Hodgkin lymphoma. Immunohistochemistry-based cell-of-origin (COO) classification via the Hans algorithm divides DLBCL into germinal centre B-cell (GCB) and activated B-cell / non-GCB subtypes, each with distinct biology and, historically, prognosis.
GCB Subtype (~50%)
- CD10+, BCL6+, MUM1- by Hans algorithm
- Enriched for BCL2 translocations and GNA13/EZH2 mutations
- Historically better prognosis with R-CHOP
Non-GCB / ABC Subtype (~50%)
- CD10-, MUM1+ (or BCL6- with MUM1+) by Hans algorithm
- Chronic active BCR/NF-κB signalling — MYD88, CD79B mutations
- Historically inferior outcomes with R-CHOP alone; rationale for BTK-inhibitor and lenalidomide combinations
| Entity | Key Feature |
|---|---|
| Double-hit lymphoma (HGBL) | MYC + BCL2 and/or BCL6 rearrangement — aggressive biology, inferior outcomes with R-CHOP, often treated with intensified regimens (e.g. DA-EPOCH-R) |
| Triple-hit lymphoma | MYC + BCL2 + BCL6 rearrangements — rare, very aggressive |
| Transformed follicular lymphoma | DLBCL arising from underlying indolent follicular lymphoma — assess for concurrent FL component |
| Primary mediastinal B-cell lymphoma (PMBL) | Distinct entity, mediastinal mass in young patients, treated per DLBCL-adjacent protocols (often DA-EPOCH-R) rather than classic R-CHOP |
IPI (5 factors, 1 point each)
- Age >60 years
- Ann Arbor Stage III/IV
- Elevated serum LDH
- ECOG performance status ≥2
- >1 extranodal site of involvement
0-1 = Low; 2 = Low-intermediate; 3 = High-intermediate; 4-5 = High risk
NCCN-IPI (Refined Model)
- Refines age into 3 categories (≤40, 41-60, 61-75, >75) rather than binary
- Refines LDH ratio into normal, >1-3×, and >3× ULN
- Better discriminates outcomes across risk groups than classic IPI
- Preferred in modern trials and clinical practice
| NCCN-IPI Group | Score | 5-yr OS (approx.) |
|---|---|---|
| Low | 0-1 | ~96% |
| Low-intermediate | 2-3 | ~82% |
| High-intermediate | 4-5 | ~64% |
| High | ≥6 | ~33% |
Viva Questions & Clinical Pearls
Q: What FISH abnormalities define double-hit lymphoma and why does it matter?
A: Concurrent MYC and BCL2 (and/or BCL6) rearrangements define high-grade B-cell lymphoma with MYC/BCL2 (and/or BCL6) rearrangements — these patients have aggressive biology and inferior outcomes with standard R-CHOP, prompting consideration of intensified regimens like DA-EPOCH-R.
Q: How does NCCN-IPI improve on the classic IPI?
A: It refines the binary age and LDH cutoffs into more granular categories, providing better discrimination of outcomes, particularly separating the highest-risk patients more accurately than the original IPI.
Q: Which extranodal sites carry elevated CNS relapse risk independent of the numerical CNS-IPI score?
A: Testicular, renal/adrenal, and breast involvement are classically considered high-risk sites for CNS relapse regardless of the calculated CNS-IPI score.
Clinical Decision Support
Pair these clinical notes with our validated calculators for a complete decision workflow.
Clinical reference only. These notes are intended to support, not replace, clinical judgment. Treatment decisions should be individualised based on patient-specific factors, local protocols, and multidisciplinary team input. Always apply clinical judgment and consult local institutional guidelines where applicable.