Background: Accelerated chronic lymphocytic leukemia (aCLL) is a rare histological variant of chronic lymphocytic leukemia (CLL), accounting for less than 1% of all diagnosed cases. The histological criteria for aCLL, defined by Giné et al. in 2010, include the presence of expanded proliferation centres (> 1 field at 20x magnification) and a high proliferative activity (Ki-67 > 40% or mitotic count > 2.4 per proliferation centre). aCLL exhibits a more aggressive clinical behaviour, sharing some features with Richter's transformation (RT), and has an intermediate prognosis between CLL and RT. The optimal therapeutic strategies for patients with this diagnosis have yet to be identified, and data on the efficacy of new targeted therapies are extremely limited. Aim: To evaluate the prevalence, clinical and biological characteristics, and treatment response of aCLL, with a particular focus on the efficacy of targeted therapies. Materials and methods: We analysed data from 199 CLL patients affiliated with the Haematology Unit of Padua, who between 2010 and 2024 underwent at least one tissue biopsy, including bone marrow biopsies. Among them, 29 cases of aCLL, 17 cases of RT, and 155 cases of CLL were identified and the clinical, biological, and metabolic data of the three histological subgroups were compared. Prognosis and treatment response were assessed based on overall survival (OS) and relapse-free survival (RFS). Results: The prevalence of aCLL among CLL patients undergoing tissue biopsy was 14.5%. Histological examination revealed that Ki67 proliferation index in aCLL was significantly higher than in CLL (p<0.001) and lower than in RT (p<0.001). Compared to CLL, patients with aCLL more frequently presented with B symptoms (p<0.001), lymphadenopathy (p=0.002), including those > 5 cm (p<0.001), bulky disease (p<0.001), extranodal involvement (p<0.001), more advanced Rai (p=0.004) and Binet (p<0.001) stages, elevated serum LDH (p=0.004) and β2-microglobulin (p=0.005) levels, unmutated IGHV genes (p=0.007), and a higher number of chromosomal abnormalities in classical cytogenetics (p=0.024). The distribution of chromosomal abnormalities on FISH (del(11q), del(13q), del(17p), trisomy 12) did not differ between the three histological groups. The frequency of TP53 mutations in aCLL was similar to RT and approximately twice as frequent as in CLL. On 18F-FDG PET-CT, aCLL showed significantly lower maximum SUV compared to RT (p<0.001) and higher than CLL (p<0.001). The prognosis of aCLL was intermediate, significantly worse than CLL (OS 63 months vs. 121.12 months, p=0.0066), but not as poor as RT (OS 63 months vs. 7.5 months, p=0.006). In first-line or subsequent therapies, 22 patients with aCLL were treated with targeted therapies: patients treated with BTKi in the first line showed significantly lower RFS compared to CLL patients (p=0.0181), while those treated with BCL2i in the first line had a similar RFS to CLL patients (p=0.6771) with median RFS not reached. Additionally, 2 patients treated with BCL2i achieved complete responses with MRD negativity. In subsequent therapy lines, RFS was significantly lower than in CLL for all three treatment types analysed (p=0.9105). During follow-up, 2 patients with aCLL treated with targeted therapies progressed to RT. Conclusions: aCLL is an underdiagnosed histological variant of CLL, with more aggressive clinical and biological features compared to CLL, which overlap with those of RT. Targeted therapies with BCL2 inhibitors showed improved RFS, with even deep responses, although of shorter duration compared to CLL. Nevertheless, aCLL presents with an intermediate prognosis, highlighting the need for early diagnosis and specific treatments. Tissue biopsy, not necessarily lymph node-based, is essential for the effective management of these patients, though further studies are required to determine the most suitable therapeutic strategies for aCLL.
Presupposti dello studio: La leucemia linfatica cronica accelerata (aCLL) è una rara variante istologica di leucemia linfatica cronica (CLL), che rappresenta meno dell’1% di tutti i casi diagnosticati. I criteri istologici per la aCLL, definiti da Giné et al. nel 2010, includono la presenza di centri proliferativi (CP) espansi (> 1 campo a 20x) e un’elevata attività proliferativa (Ki-67 > 40% o numero di mitosi > 2,4 per CP). La aCLL ha un comportamento clinico più aggressivo rispetto alla CLL, condividendo alcune caratteristiche con la trasformazione di Richter (RT), e una prognosi intermedia tra la CLL e la RT. Non sono state ancora identificate le migliori strategie terapeutiche e i dati sull’efficacia delle nuove target therapy sono estremamente limitati. Scopo dello studio: Valutare la prevalenza, le caratteristiche cliniche e biologiche della aCLL e la risposta ai trattamenti, in particolare alle target therapy. Materiali e metodi: Sono stati analizzati i dati di 199 pazienti con CLL afferenti all’Unità di Ematologia di Padova, sottoposti dal 2010 al 2024 ad almeno una biopsia tissutale, incluse le biopsie osteomidollari. Tra questi, sono stati identificati 29 casi di aCLL, 17 casi di RT e 155 casi di CLL e sono stati confrontati i dati clinici e biologici dei tre sottogruppi istologici. La prognosi e la risposta ai trattamenti sono state valutate in base agli esiti di sopravvivenza globale (OS) e libera da recidiva (RFS). Risultati: La prevalenza della aCLL tra i pazienti con CLL sottoposti a biopsia tissutale è risultata pari al 14,5%. All’esame istologico, l’indice di proliferazione Ki67 nella aCLL era significativamente più alto rispetto alla CLL (p<0,001) e più basso rispetto alla RT (p<0,001). Rispetto alla CLL, i pazienti con aCLL presentavano più sintomi B (p<0,001), linfoadenopatie (p=0,002), anche > 5 cm (p<0,001), malattia bulky (p<0,001), coinvolgimento extra-nodale (p<0,001), stadio Rai (p=0,004) e Binet (p<0,001) più avanzato, livelli di LDH (p=0,004) e β2-microglobulina (p=0,005) aumentati, stato IGHV non mutato (p=0,007) e alterazioni del cariotipo (p=0,024). La distribuzione delle alterazioni cromosomiche alla FISH non differiva tra i tre gruppi istologici. La frequenza delle mutazioni di TP53 nella aCLL era simile alla RT e circa doppia rispetto la CLL. Alla PET-TC con 18-FDG la aCLL presentava un SUVmax significativamente inferiore rispetto alla RT (p<0,001) e superiore rispetto alla CLL (p<0,001). La prognosi della aCLL è risultata intermedia, significativamente inferiore alla CLL (OS 63 vs 121,12 mesi, p=0,0066) ma non così sfavorevole come la RT (OS 63 vs 7,5 mesi, p=0,006). 22 pazienti con aCLL sono stati trattati con le target therapy: in prima linea, i pazienti trattati con BTKi hanno mostrato RFS significativamente inferiori rispetto ai pazienti con CLL (p=0,0181), i pazienti trattati con BCL2i, invece, hanno ottenuto RFS simili ai pazienti con CLL (p=0,6771) con RFS mediana non raggiunta. Inoltre, 2 pazienti trattati con BCL2i hanno ottenuto risposte complete con MRD negativa. Nelle linee successive, la RFS è risultata significativamente più bassa rispetto alla CLL per tutti i tipi di trattamento analizzati (p=0,9105). Durante il follow-up, 2 pazienti con aCLL sono evoluti in RT. Conclusioni: La aCLL è una variante istologica della CLL sottodiagnosticata, caratterizzata da un profilo clinico e biologico più aggressivo rispetto alla CLL e simile a quello della RT. Le target therapy con gli inibitori di BCL2 sembrano determinare RFS migliori, con risposte anche profonde, sebbene di durata inferiore rispetto alla CLL. Nonostante ciò, la aCLL presenta una prognosi intermedia, evidenziando la necessità di una diagnosi precoce e di trattamenti mirati. La biopsia tissutale, non necessariamente linfonodale, è fondamentale per una corretta gestione di questi pazienti, ma sono necessari ulteriori studi per definire le migliori strategie terapeutiche per la aCLL.
Prevalenza, impatto clinico e risposta ai trattamenti della leucemia linfatica cronica accelerata
SCARPA, ALESSIA
2023/2024
Abstract
Background: Accelerated chronic lymphocytic leukemia (aCLL) is a rare histological variant of chronic lymphocytic leukemia (CLL), accounting for less than 1% of all diagnosed cases. The histological criteria for aCLL, defined by Giné et al. in 2010, include the presence of expanded proliferation centres (> 1 field at 20x magnification) and a high proliferative activity (Ki-67 > 40% or mitotic count > 2.4 per proliferation centre). aCLL exhibits a more aggressive clinical behaviour, sharing some features with Richter's transformation (RT), and has an intermediate prognosis between CLL and RT. The optimal therapeutic strategies for patients with this diagnosis have yet to be identified, and data on the efficacy of new targeted therapies are extremely limited. Aim: To evaluate the prevalence, clinical and biological characteristics, and treatment response of aCLL, with a particular focus on the efficacy of targeted therapies. Materials and methods: We analysed data from 199 CLL patients affiliated with the Haematology Unit of Padua, who between 2010 and 2024 underwent at least one tissue biopsy, including bone marrow biopsies. Among them, 29 cases of aCLL, 17 cases of RT, and 155 cases of CLL were identified and the clinical, biological, and metabolic data of the three histological subgroups were compared. Prognosis and treatment response were assessed based on overall survival (OS) and relapse-free survival (RFS). Results: The prevalence of aCLL among CLL patients undergoing tissue biopsy was 14.5%. Histological examination revealed that Ki67 proliferation index in aCLL was significantly higher than in CLL (p<0.001) and lower than in RT (p<0.001). Compared to CLL, patients with aCLL more frequently presented with B symptoms (p<0.001), lymphadenopathy (p=0.002), including those > 5 cm (p<0.001), bulky disease (p<0.001), extranodal involvement (p<0.001), more advanced Rai (p=0.004) and Binet (p<0.001) stages, elevated serum LDH (p=0.004) and β2-microglobulin (p=0.005) levels, unmutated IGHV genes (p=0.007), and a higher number of chromosomal abnormalities in classical cytogenetics (p=0.024). The distribution of chromosomal abnormalities on FISH (del(11q), del(13q), del(17p), trisomy 12) did not differ between the three histological groups. The frequency of TP53 mutations in aCLL was similar to RT and approximately twice as frequent as in CLL. On 18F-FDG PET-CT, aCLL showed significantly lower maximum SUV compared to RT (p<0.001) and higher than CLL (p<0.001). The prognosis of aCLL was intermediate, significantly worse than CLL (OS 63 months vs. 121.12 months, p=0.0066), but not as poor as RT (OS 63 months vs. 7.5 months, p=0.006). In first-line or subsequent therapies, 22 patients with aCLL were treated with targeted therapies: patients treated with BTKi in the first line showed significantly lower RFS compared to CLL patients (p=0.0181), while those treated with BCL2i in the first line had a similar RFS to CLL patients (p=0.6771) with median RFS not reached. Additionally, 2 patients treated with BCL2i achieved complete responses with MRD negativity. In subsequent therapy lines, RFS was significantly lower than in CLL for all three treatment types analysed (p=0.9105). During follow-up, 2 patients with aCLL treated with targeted therapies progressed to RT. Conclusions: aCLL is an underdiagnosed histological variant of CLL, with more aggressive clinical and biological features compared to CLL, which overlap with those of RT. Targeted therapies with BCL2 inhibitors showed improved RFS, with even deep responses, although of shorter duration compared to CLL. Nevertheless, aCLL presents with an intermediate prognosis, highlighting the need for early diagnosis and specific treatments. Tissue biopsy, not necessarily lymph node-based, is essential for the effective management of these patients, though further studies are required to determine the most suitable therapeutic strategies for aCLL.File | Dimensione | Formato | |
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https://hdl.handle.net/20.500.12608/78614