Latest Staging System for DLBCL
The Lugano classification is the current gold standard staging system for diffuse large B-cell lymphoma (DLBCL), which modified the traditional Ann Arbor system and was formally adopted in 2014. 1
Core Staging Framework
The Lugano classification uses a modified Ann Arbor staging approach with the following stages: 1
- Stage I: Involvement of a single lymph node region or single extralymphatic organ (IE)
- Stage II: Two or more nodal groups on the same side of the diaphragm, or localized extralymphatic involvement with regional nodes (IIE)
- Stage II bulky: Stage II disease with bulky features (single mass ≥10 cm or >1/3 transthoracic diameter)
- Stage III: Nodal involvement on both sides of the diaphragm; spleen involvement is considered nodal tissue
- Stage IV: Disseminated involvement of one or more extralymphatic organs with or without nodal disease
Key Innovations of the Lugano System
PET-CT as the Gold Standard
PET-CT is now the recommended imaging modality for staging all FDG-avid lymphomas including DLBCL, replacing contrast-enhanced CT as the primary staging tool. 1 This represents the most significant change from historical practice, as PET-CT demonstrates superior sensitivity for both nodal and extranodal disease sites. 1
Bone Marrow Assessment Changes
Bone marrow biopsy is no longer required when PET-CT demonstrates bone or marrow involvement indicating advanced-stage disease. 1 However, biopsy remains appropriate when PET is negative and identifying low-volume (<10-20%) or discordant lymphoma would change treatment decisions, particularly when abbreviated chemotherapy cycles are being considered. 1
Elimination of Outdated Designations
The Lugano classification eliminated several elements: 1
- The "X" designation for bulky disease is no longer used; instead, the largest tumor diameter should be recorded in centimeters
- The A/B suffix (presence/absence of B symptoms) is only required for Hodgkin lymphoma, not DLBCL
- The "CRu" (complete response unconfirmed) category was eliminated from response assessment
Practical Staging Requirements
Mandatory Baseline Assessments
- Physical examination with performance status (ECOG) and B symptom documentation
- Complete blood count and comprehensive metabolic panel including LDH and uric acid
- Screening for HIV, hepatitis B (HBsAg, anti-HBs, anti-HBc), and hepatitis C
- PET-CT scan from skull base to mid-thigh
- Protein electrophoresis
- Cardiac function assessment (LVEF) before anthracycline-based therapy
When to Add Contrast-Enhanced CT
A diagnostic contrast-enhanced CT should be performed in addition to PET-CT when: 1
- Better delineation of bowel from lymphadenopathy is needed
- Detection of vascular compression or thrombosis is required
- Radiation therapy planning necessitates more precise anatomic detail
- Clinical trial protocols require accurate nodal measurements
Risk Stratification Integration
The International Prognostic Index (IPI) or age-adjusted IPI (aa-IPI) must be calculated using: age, LDH level, ECOG performance status, Ann Arbor stage, and number of extranodal sites. 1, 2, 3 This risk stratification directly determines treatment intensity, making it an essential component of the staging process beyond anatomic stage alone.
Common Pitfalls to Avoid
Do not delay treatment to obtain PET-CT if emergency therapy is required—core needle biopsy provides sufficient diagnostic material to initiate treatment in urgent situations. 2, 3
Do not assume all extranodal sites represent stage IV disease—localized extranodal involvement with regional nodes is stage IIE, not stage IV, which has important treatment implications for limited-stage disease. 1
Do not order routine bone marrow biopsy in all patients—this outdated practice wastes resources when PET-CT already shows advanced disease, though biopsy remains valuable when negative PET results would lead to abbreviated therapy in apparent early-stage disease. 1