Rethinking bone marrow biopsy: is PET/CT enough for staging low-grade follicular lymphomas?

Area of Science:

• Oncology
• Nuclear Medicine
• Diagnostic Imaging

Background:

• Follicular lymphoma (FL) staging relies on detecting bone marrow involvement (BMI).
• Bone marrow biopsy (BMB) is invasive and its necessity in staging low-grade FL is debated.
• 18F-FDG PET/CT is a key imaging modality for lymphoma staging.

Purpose of the Study:

• To evaluate the diagnostic performance of 18F-FDG PET/CT for BMI detection in newly diagnosed low-grade FL.
• To assess the impact of PET/CT findings on the clinical necessity of BMB.
• To identify risk factors associated with BMI in FL patients.

Main Methods:

• Retrospective analysis of 171 low-grade FL patients who underwent both 18F-FDG PET/CT and BMB.
• PET/CT diagnostic accuracy for BMI was assessed against BMB as the gold standard.
• Risk factor analysis for BMI positivity was performed, stratifying patients into risk groups.

Main Results:

• 18F-FDG PET/CT showed 86.5% accuracy in detecting BMI.
• In early-stage (I-II) FL based on PET/CT, all BMB results were negative, suggesting PET/CT can replace BMB.
• In advanced-stage (III-IV) FL, BMB upstaged 13 patients, and risk factors like female sex and ECOG score >1 predicted BMI positivity.

Conclusions:

• 18F-FDG PET/CT is a reliable tool for staging early-stage, low-grade FL, potentially obviating the need for BMB.
• BMB remains valuable for staging advanced-stage FL, especially in patients with identified risk factors.
• BMI positivity correlates with tumor burden and specific clinical risk factors.