A more accurate prognostic index for patients with mucosa-associated lymphoid tissue (MALT) lymphoma may be possible by examining the level lymphocyte-to-monocyte ratio (LMR) at diagnosis.
Researchers reported at the EHA 2022 Hybrid Congress that a low LMR at diagnosis may be associated with inferior progression-free survival (PFS) and overall survival (OS). Their findings suggest that incorporating LMR into the MALT International Prognostic Index (MALT-IPI) may permit a more accurate risk assessment of disease progression.
Extranodal marginal zone B-cell lymphoma of MALT is a unique type of indolent lymphoma, and monocytes are closely linked to the pathogenesis and disease progression, according to the study authors. The absolute monocyte count (AMC) and LMR previously had been shown to reflect the host systemic immunity states and provide prognostic benefits in different kinds of lymphoma.
The MALT-IPI was developed using a database of 401 patients treated in an international trial with chlorambucil, rituximab, or both. The index was subsequently validated by merging 3 independent cohorts of patients with MALT lymphoma.
The researchers examined the prognostic significance of AMC and LMR in 316 patients with MALT lymphoma. A statistically evident dominance showed that LMR was related to age, lactate dehydrogenase (LDH) level, β 2-microglobulin level, B symptoms, ECOG performance status, and systemic therapy. The median PFS was 146.4 months, and the median OS was not reached with a median follow-up time of 39.1 months (range, 1-237 months).
The estimated PFS rate was 84.1% at 3 years and 79.6% at 5 years. The estimated OS rate was 94.9% at 3 years and 92.4% at 5 years. The high AMC group (>0.6×109/L) and the low LMR group (<1.8) were associated with poor outcomes.
MALT-IPI, ECOG performance status, and LMR were identified as having independent prognostic significance for PFS. Additionally, MALT-IPI, β 2-microglobulin, and LMR were independently associated with poor OS.
The prognostic value of low LMR for PFS was more pronounced based on age (P value for interaction =.020). The prognostic value of low LMR was consistent across a subgroup analysis of OS.
The team combined MALT-IPI and AMC and developed a new prognostic index named MALT-IPI-M. It includes 4 parameters: age 70 years or older, Ann Arbor stage III or IV, serum LDH level greater than the upper limit of normal, and LMR less than 1.8.
The researchers found that MALT-IPI-M was able to classify patients into a low-risk group (the MALT-IPI-M=0), an intermediate-risk group (the MALT-IPI-M=1) and a high-risk group (the MALT-IPI- M≥2).
The researchers used receiver-operator characteristic (ROC) curves to compare the prognostic prediction capability of MALT-IPI and MALT-IPI-M. The areas under the curve (AUCs) for MALT-IPI-M were 0.682 for PFS and 0.804 for OS. This indicated an improved capability of distinguishing MALT patients with different risk (MALT-IPI 0.654 for PFS and 0.788 for OS).
The researchers next hope to validate their findings in multicenter prospective studies.
Disclosures are not available for this presentation.
Li Y, Shang C, Ren Y, et al. Prognostic significance of absolute monocyte count and lymphocyte to monocyte ratio in mucosa-associated lymphoid tissue (MALT). Presented at EHA 2022; June 9-12, 2022. Abstract P1118.