Diagnosis of bone marrow involvement in angioimmunoblastic T-cell lymphoma should be based on both [¹⁸F]FDG-PET/CT and bone marrow biopsy findings

Abstract

Objective

During the initial staging of certain lymphoma subtypes, 18 F-fluorodeoxyglucose positron emission tomography/computed tomography ([¹⁸F]FDG-PET/CT) has become an alternative to bone marrow biopsy (BMB) for detecting bone marrow (BM) involvement. However, whether [¹⁸F]FDG-PET/CT can accurately detect BM involvement in angioimmunoblastic T-cell lymphoma (AITL) remains unknown. Our study aimed to assess the diagnostic and prognostic capability of [¹⁸F]FDG-PET/CT for detecting BM involvement in AITL. Methods: This retrospective study included 84 individuals newly diagnosed with AITL who underwent baseline BMB and [¹⁸F]FDG-PET/CT. “BM involvement” was defined as one or both of the following: 1) angioimmunoblastic T-cells detected in the BM; or 2) initially heightened focal uptake having disappeared on follow-up [¹⁸F]FDG-PET/CT. The ability of [¹⁸F]FDG-PET/CT to detect BM cancerous lesions was respectively analyzed by BM involvement confirmed by BMB or the aforementioned definition as the reference standard. The patients’ clinical characteristics and survival and prognostic outcomes were respectively analyzed.

Results

Of the 84 participants, five (6.0%) displayed positive BMB and PET/BM results, 17 (20.2%) had BMB-positive but PET/BM-negative results, eight (9.5%) showed BMB-negative but PET/BM-positive outcomes, and 54 (64.3%) displayed negative BMB and PET/BM outcomes. Using pre-defined BM involvement as the reference standard, [¹⁸F]FDG-PET/CT exhibited a specificity of 100%, sensitivity of 40%, negative predictive value (NPV) of 75%, and positive predictive value (PPV) of 100%. In contrast, using BMB-detected BM involvement as reference, [¹⁸F]FDG-PET/CT exhibited a sensitivity, specificity, PPV, and NPV of 38.5%, 76.1%, 22.7%, and 87.1%, respectively. Among patients with PET/BM-positive and BMB-negative outcomes, 62.5% (5/8) underwent upstaging from III to IV. In 58.8% (10/17) of patients who were initially diagnosed with stage II/III disease based on the [¹⁸F]FDG-PET/CT results, repeat BMB resulted in upstaging to IV. PET/BM-negative patients had a higher 3-year progression-free survival rate (38.3% vs. 22.8%, p = 0.018) and 3-year overall survival rate (64.4% vs. 34.6%, p = 0.011) than PET/BM-positive patients.

Conclusion

In AITL patients, PET/BM-positive results may obviate the necessity for repeat BMB to ascertain confirm BM involvement. PET/BM-negative results do not definitively exclude BM involvement. The combined use of [¹⁸F]FDG-PET/CT and BMB can increase the diagnostic accuracy of BM involvement for AITL patients.

Keywords:

• [18F]fdg-pet/CT
• AITL
• bone marrow
• diagnosis
• prognosis

Transparency

Declaration of funding

This study received no funding.

Declaration of financial/other relationships

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties. A reviewer on this manuscript has disclosed that they serve an advisory role for Novartis Radiopharmaceuticals GmbH. Peer reviewers on this manuscript have received an honorarium from CMRO for their review work but have no other relevant financial relationships to disclose.

Author contributions

Xinyu Liang: Conception and design; analysis and interpretation of the data; writing – original draft; Chunli Yang: Writing – original draft; revising it critically for intellectual content; Minggang Su: interpretation of the data; revising draft; Liqun Zou: Conception and design; the final approval of the version to be published. All authors agree to be accountable for all aspects of the work.

Acknowledgements

Authors appreciate pathology professors Weiping Liu and Yan Zhang (West China Hospital of Sichuan University) for diagnosing AITL and interpreting the BMB histological results.

Data availability statement

The data used to support the findings of this study are available from the corresponding author upon request.

Ethical approval

The Ethics Committee of West China Hospital approved this research (approval ID: SCHX‐2022‐64).