Background: Acute lymphoblastic leukemia/lymphoma (ALL/LBL) is a rare, genomically heterogenous group of diseases with 20% of cases being diagnosed in adults. Among adults with ALL/LBL, T cell-ALL/LBL (T-ALL/LBL) accounts for 20-25% of cases. The real-world incidence, outcomes, and regional variance of T-ALL subtypes such as Early T-cell Precursor ALL/LBL (ETP-ALL/LBL), in adults remains less well characterized. Here we describe the presentation and outcomes of T-ALL at a single NCI-designated comprehensive cancer center in the Deep South.

Methods: We conducted a retrospective chart review of patients diagnosed with T-ALL at our center from 2016 to 2024. Institutional Review board approval was obtained. Demographic, outcomedata was abstracted and descriptive statistics were performed. Kaplan Meier Survival Analysis was performed using SPSS.

Results: A total of 215 patients were diagnosed with ALL/LBL at our institution between 2016-2024. In this cohort, 44 cases of T-ALL/LBL (20%) were identified, including 8 T-LBL cases (4% of all ALL, 18% of T-ALL). Incidence of ETP-ALL/LBL was 38% (17/44). Eighteen patients (41%) were female. Median age at presentation was 43 years for T-ALL/LBL, 34 years for T-LBL, and 52 vs 41 years for ETP and non-ETP phenotype, respectively (p= 0.08). Seventeen patients (38%) were in the NCI defined adolescent and young adult age group (AYA) between 16-39 years, of which 29% (5/17) had ETP phenotype compared to 44% in those over 40 years of age. Racially, 45% of all patients identified as Black, 50% as White, and 5% as Asian or other. The incidence of T-ALL/LBL was 40% in Black patients, compared to 15% in White patients (P<0.00001). The proportion of ETP-ALL did not differ by race. KMT2A and t(9;22) rearrangements were seen 6% and 11.3% respectively. CNS disease (CNS 3 or symptomatic disease) at initial presentation was present in 7% patients with no difference between the ETP and non-ETP subgroups. Thirteen patients (30%) received a pediatric-inspired regimen containing pegasparginase. Transplantation rate was 26% (11/43; 1 patient with inadequate follow up) among all T-ALL/LBLs, 37.5% (6/16) for ETP-ALL, and 18.5% (5/27) for non-ETP ALLs. Only 2 patients in the AYA age group underwent transplantation in second remission. Median OS (mOS) for the entire cohort was 18.7 months, while the mOS for ETP-ALL and non-ETP ALL was 10 months vs 25 months, respectively (p=0.006), and not reached for T-LBL patients. There was no difference in survival by race. mOS for the AYA population was not reached compared to 13.7 months for those 40 years and over (p=0.09). mOS for AYA patients with ETP vs non-ETP was 6 months vs not reached; in adults 40 and over, this was 10.3 months vs 25 months. mOS for ETP-ALL was 14 vs 7 months for those who did or did not undergo allogeneic transplant (p=0.01), while there was no difference in survival for the non-ETP patients based on transplant status.

Conclusion: To the best of our knowledge, this is the second report on a real-world cohort of adult T-ALL patients from the Deep South, however the first report from a more recent cohort of patients in the past 10 years. We report a higher incidence of T-ALL in Black patients in comparison to White patients, but with no observed differences in outcomes by race. While there is conflicting data about the prognostic impact of ETP phenotype in adults, our cohort demonstrates significantly worse outcomes for the ETP subtype, irrespective of age, race or pegasparginase containing regimens and a benefit for allogeneic transplantation in this population. Given the small number of AYA patients, definitive conclusions regarding ETP vs non-ETP and regimen-specific outcomes is not feasible. We did also note a rather low transplantation rate in our cohort as well as a higher than usual reported incidence of Ph+ T ALL/LBL. In Summary , while acknowledging the limitations of the small number of patients in this retrospective study, it does highlight 1) that ETP-ALL/LBL remains a high-risk subset of patients in need for better therapies 2) the need to better understand the barriers to allogeneic transplantation in adults with T-ALL in the deep south 3) that Ph+ T-ALL/LBL maybe a previously underrecognized entity.

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2025
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