Key Imaging Guidelines for Lymphoma: ESOI Recommendations

Overview

The European Society of Oncologic Imaging recommends [18F]FDG-PET/CT as the preferred imaging modality for staging and response assessment in Hodgkin lymphoma and most aggressive and indolent Non-Hodgkin lymphomas. CT is reserved for small lymphocytic lymphoma/chronic lymphocytic leukemia and non-FDG-avid indolent NHL. The Deauville 5-point scale is endorsed for PET response evaluation.

Background

Lymphomas are a heterogeneous group of lymphatic system malignancies with diverse subtypes differing in prognosis and treatment, including novel immunotherapies like CAR T-cells. Imaging is critical for initial detection, staging, treatment response assessment, and biopsy guidance. The WHO classification distinguishes Hodgkin lymphoma and various Non-Hodgkin lymphoma subtypes, which informs imaging modality selection. PET/CT and contrast-enhanced CT are the main imaging tools, with PET/CT favored for FDG-avid lymphomas.

Data Highlights

Imaging modality recommendations by lymphoma subtype category:
• Routinely FDG-avid (e.g., Hodgkin lymphoma, DLBCL, follicular lymphoma): PET/CT for staging and response.
• Non-FDG-avid (e.g., SLL/CLL): CE-CT for staging and response; PET/CT if transformation suspected.
• Variably FDG-avid (e.g., marginal zone lymphoma, cutaneous T-cell lymphoma): PET/CT at baseline; CE-CT if non-FDG-avid.

Diagnostic criteria:
• Lymph nodes >1.5 cm long-axis diameter considered suspicious.
• SUVmax >5 on PET suggests Richter transformation in SLL/CLL.

Imaging roles:
• PET/CT detects treatment response earlier than CT.
• MRI standard for CNS lymphoma and problem-solving in marrow lesions.
• PET/MRI emerging but not yet guideline standard.

Key Findings

• [18F]FDG-PET/CT is the preferred imaging modality for staging and response assessment in Hodgkin lymphoma and most aggressive and indolent NHL subtypes.
• CT is the imaging modality of choice for small lymphocytic lymphoma/chronic lymphocytic leukemia and non-FDG-avid indolent NHL, with PET/CT reserved for suspected transformation.
• The Deauville 5-point scale (5-PS) is recommended for PET-based treatment response assessment.
• Lymph nodes with a long-axis diameter >1.5 cm are considered suspicious for lymphoma involvement.
• MRI is the standard for CNS lymphoma and useful for equivocal bone marrow lesions; whole-body MRI is an option in special populations.
• Terminology in lymphoma imaging avoids “primary” and “metastasis,” favoring “nodal” and “extranodal” manifestations.

Clinical Implications

Clinicians should select imaging modalities based on lymphoma subtype FDG avidity to optimize staging and response assessment accuracy. PET/CT enables earlier detection of treatment response and is preferred for most lymphomas, while CT remains essential for non-FDG-avid subtypes. Familiarity with lymphoma-specific imaging terminology and nodal size criteria improves diagnostic consistency and communication.

Conclusion

The ESOI guidelines emphasize tailored imaging strategies for lymphoma subtypes, prioritizing [18F]FDG-PET/CT for FDG-avid lymphomas and CT for others, with standardized response criteria to enhance patient management. Integration of advanced imaging modalities continues to evolve, supporting precision oncology in lymphoma care.

References

1. WHO Classification of Lymphoid Neoplasms, 5th Edition
2. ESOI PRoLoG Consensus on Lymphoma Imaging, 2023
3. Lugano Classification for Lymphoma Staging and Response Assessment, 2014