Three-Year Analysis of Patient Demographics and Clinical characteristics in the Rare Entity of Lymphoblastic Lymphoma (LBL) in the Netherlands
Lymphoblastic lymphoma (LBL) is a rare, aggressive malignancy, most commonly of T-cell origin, and shares biological features with acute lymphoblastic leukemia (ALL). LBL is distinguished by limited bone marrow involvement (defined as <20%). To better understand this disease, we initiated a national registry collecting clinical, pathological, molecular, and imaging data, including PET-CT response, from adult LBL patients. This registry aims to provide insight into patient characteristics and current practices, with potential to identify prognostic factors in a real-world setting. Here we present data from the first 31 patients.
We conducted a partially retrospective, mainly prospective study across six Dutch centres. Adult patients newly diagnosed with LBL from 2018 onwards were included if PET-CT was performed at diagnosis.
Thirty-one patients were included. Median age at diagnosis was 45.4 years (range 22–76); 77.4% were male. Most cases were of T-cell origin (n=23, 74.2%), and 54.8% were Ann Arbor stage IV. Patients were generally in good condition (83.9% WHO 0–1), with low comorbidity scores (76% had age-adjusted HCT-CI 0–1). B-symptoms were present in 29%, and 22.6% had superior vena cava syndrome as a presenting symptom. Elevated LDH was found in 54.8%. CNS involvement occurred in 9.7%, with only one symptomatic case. Cytogenetics of BM (n=25) showed mostly normal karyotypes (n=20); two patients had a BCR::ABL1 fusion.
Baseline PET-CT showed mediastinal involvement in 67.7% and pleuropericardial involvement in 41.9%, particularly in T-LBL (82.6% and 52.2%). B-LBL (n=8) showed more diffuse uptake (skin, liver, spleen in 37.5%). SUVmax was extractable in six patients (median 9.5). Bone marrow aspiration was performed in all but two patients (initially misdiagnosed as NHL); median BM blasts were 0.18% (range 1.72-7.80%). Ki-67 index (>90%) was increased in 74.2%. Most patients (93.5%) received intensive chemotherapy (e.g., HOVON100-like regimen). A total of six patients underwent alloSCT.
Two patients experienced relapse during initial treatment. Five additional relapses occurred during or after maintenance therapy, including two after alloSCT. Two patients died, one while in complete remission and one after relapse, and one patient was lost to follow-up.
This Dutch cohort highlights the clinical features of adult LBL. Despite its rarity, systematic data collection reveals patterns that may guide future diagnostics and treatment. Expanding the registry, by both involving more participating centres and through planned collaboration with nuclear medicine to explore the prognostic value of PET-CT will be key to unlocking insights and improving outcomes for this aggressive lymphoma.