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4401 Impact of Bone Marrow Evaluation Using Bone Marrow Biopsy, Flow Cytometry, and PET/CT in B-Cell Non-Hodgkin Lymphomas

Program: Oral and Poster Abstracts
Session: 623. Mantle Cell, Follicular, Waldenstrom’s, and Other Indolent B Cell Lymphomas: Clinical and Epidemiological: Poster III
Hematology Disease Topics & Pathways:
Research, Non-Hodgkin lymphoma, Lymphomas, Clinical Practice (Health Services and Quality), Clinical Research, B Cell lymphoma, Diseases, Indolent lymphoma, Real-world evidence, Aggressive lymphoma, Registries, Lymphoid Malignancies, Survivorship, Study Population, Human
Monday, December 9, 2024, 6:00 PM-8:00 PM

José Antonio Sánchez Salas, MD1*, Estela Ruiz Ruiz, MD2*, Almudena Cascales Hernandez, MD2*, Joaquin Gomez Espuch, MD, PhD3*, Andrea Poveda Garcia, MD2*, Angela Heredia Cano, MD2*, Miguel Blanquer Blanquer, MD, PhD4, Maria Carmen GARCIA Garay, MD3*, Antonio Jose Martinez Mellado2*, Alfredo Minguela Puras, PhD5*, Agueda Bas Bernal, MD6*, Vanessa Roldan Schilling, MD, PhD2* and Antonio Salar Silvestre, MD, PhD7*

1Hematology, Virgen de la Arrixaca University Hospital, Murcia (Spain), Guadix, Spain
2Hematology, Virgen de la Arrixaca University Hospital, Murcia (Spain), El Palmar, Murcia, Spain
3Hematology, Hospital Universitario Virgen de la Arrixaca, Murcia, Spain
4Hematology, Hospital Clínico Universitario Virgen De La Arrixaca, Murcia, Spain
5Immunology, Virgen de la Arrixaca University Hospital, Murcia (Spain), El Palmar, Murcia, Spain
6Pathology, Virgen de la Arrixaca University Hospital, Murcia (Spain), El Palmar, Murcia, Spain
7Hematology, Virgen de la Arrixaca University Hospital, Murcia (Spain), Murcia, Spain

Introduction

The initial evaluation and staging of non-Hodgkin lymphomas (NHL) are currently conducted according to the Lugano classification (2014). The incorporation of PET/CT and other techniques such as flow cytometry (FCM) and molecular studies into routine clinical practice has recently questioned the utility of bone marrow biopsy (BMB) in the initial work-up of NHL. Our study aimed to evaluate bone marrow (BM) involvement through BMB and FCM, and also by PET/CT in patients with B-cell NHL. We assessed the impact of each method on lymphoma staging and their ability to discriminate progression-free survival (PFS) and overall survival (OS).

Material and Methods

This observational retrospective study consecutively included all patients with B-cell NHL of any histological type who underwent BM evaluation between 2019 and 2023 at a single tertiary hospital. Inclusion criteria were: > 18 years, B-cell NHL and BM evaluation through aspiration/trephine biopsy at diagnosis at our center. Diagnoses were grouped into indolent NHL (follicular lymphoma (FL), marginal zone lymphoma (MZL), or other indolent lymphomas) or aggressive NHL (diffuse large B-cell lymphoma (DLBCL), mantle cell lymphoma (MCL), or other aggressive lymphomas).

The Ann Arbor (AA) stage was initially defined based on clinical and imaging findings by PET/CT without considering BM (AA-baseline), and subsequently incorporating BMB (AA-BMB), FCM (AA-FCM), and PET/CT considering BM findings (AA-PET). FCM was performed in BM aspirate according to EuroFlow based methods (at least eight colors) resulting in a general sensitivity between 10-3 and 10-4. Concordance Index (C-Index), Akaike Information Criterion (AIC), and estimated concordance probability (CPE) were used to evaluate discrimination for PFS and OS.

Results

A total of 224 patients were identified, of whom 134 (59%) met the inclusion criteria. The median age was 64 years (range 19-91) with 65.1% being male. Of the total number of patients, 219 (97.8%) were caucasian, 4 (1.8%) were arab, and 1 (0.4%) was black. Histologies were as follows: FL 25.4%, MZL 19.4%, other indolent NHL 2.2%, DLBCL 41.8% and MCL 11.2%. BMB was performed in 85.2%, CFM in 95.5% and PET/CT in 83.9%.

A total of 123 patients (91.8%) received treatment: 21 (15.7%) rituximab monotherapy, 77 (57.5%) rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP), 15 (11.2%) R plus other chemotherapy combinations, 2 (1.5%) radiotherapy (RT), and 8 (5.9%) other treatments. The AA-baseline stage was I: 18.0%, II: 15.0%, III: 28.6%, and IV: 38.35%.

The addition of BMB, FCM, and PET/CT resulted in upstaging in 16.5% (AA-BMB), 16.3% (AA-FCM), and 7.3% (AA-PET) of the patients, respectively. Interestingly, upstaging by BMB and FCM was higher in aggressive NHL (21.4% and 23.5%, respectively) compared to indolent NHL (11.1% and 8.2%, respectively). This fact was also observed in the case of PET/CT, although with a lower percentage of upstaging compared to the other two techniques (10.0% in aggressive NHL and 4.1% in indolent NHL).

The 5-year PFS and OS were 63.5% (95%CI 53.1-76.0) and 79.3% (95%CI 70.9-88.8), respectively. Differences in discrimination for PFS and OS were observed through the 3 techniques, but varied according to NHL group. In indolent NHL, the addition of BMB findings (AA-BMB) to AA-baseline showed a higher C-Index for PFS (0.620 vs. 0.591) and for OS (0.683 vs. 0.597). In the AIC analysis, AA-PET showed the highest discrimination for PFS (86.2941 vs. 111.7166 for the AA-baseline). However, according to the CPE analysis, AA-BMB showed the highest discrimination for PFS compared with AA-baseline (0.604 vs. 0.6038, respectively) and, in particular, for OS (0.7337 vs. 0.5654, respectively). A similar trend was observed in aggressive NHL, with a C-Index for PFS showing identical results (0.572) for both AA-BMB and AA-PET, without clear predominance of one test over the others.

Conclusion

In the staging of NHL, evaluation of bone marrow involvement through BMB or high sensitivity FCM upstages patients in a higher proportion compared to PET/CT. Including BMB in the staging process results in a slight improvement in survival discrimination, particularly in indolent NHL. Our data are in favor of keeping assessment of BM through BMB in the work-up at diagnosis, at least in indolent NHL.

* JA. S. and E. R. are equally contributed authors.

Disclosures: Salar Silvestre: Incyte: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Ipsen: Membership on an entity's Board of Directors or advisory committees; Sandoz: Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees; Roche: Speakers Bureau; BeiGene: Speakers Bureau.

*signifies non-member of ASH