Type of publication:
Conference abstract
Author(s):
*Arunachalam J.; Meleveedu K.
Citation:
HemaSphere. Conference: 30th Congress of the European Hematology Association Annual Congress, EHA2025. Milan Italy. 9(Supplement 1) (pp 1319-1321), 2025. Date of Publication: 01 Jun 2025.
Abstract:
Background Anaplastic lymphoma kinase-positive (ALK+) large B-cell lymphoma (LBCL) is a rare subtype of diffuse large B-cell lymphoma (DLBCL), representing < 1% of all DLBCLs. Tumor growth is driven by ALK gene rearrangements which lead to proto-oncogene activation. Unlike ALK-positive anaplastic large-cell lymphoma (ALCL), ALK+ LBCL shows plasmablastic immunophenotype and often lacks typical T cell (CD2, CD3) and B-cell (CD20, CD79a) markers. It is known to be more aggressive than typical DLBCL due to limited response to conventional systemic chemotherapies like R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone), with a dismal 5-year OS of 8% in advanced stage disease. Off-label use of ALK inhibitors has demonstrated encouraging results in multiple case studies. Aims This study aims to analyze the incidence trends, and survival outcomes of ALK+ LBCL using the Surveillance, Epidemiology, and End Results database. SEER provides population-based data on cancer incidence, survival, and treatment outcomes by compiling various cancer registries across the U.S. Methods We conducted a retrospective population-based study between 2010-2021 utilizing the SEER database. Using ICD code 9737/3, we identified patients diagnosed with ALK+ LBCL. Demographic data, including age, sex, race, and stage, were collected. Incidence rates (IR) were calculated per 100,000 and age adjusted to the US standard population. Kaplan-Meier survival analysis was performed using GraphPad Prism to estimate overall survival (OS) and cancer specific survival (CSS). Log rank test was used to detect factors associated with survival outcomes. Results A total of 58 cases of ALK+ LBCL were included. IR was 0.0049 (SE 0.0010, 95% CI 0.0031-0.0073) during the years 2010-2015 and 0.0067 (SE 0.0011, 95% CI 0.0047-0.0094) from 2016-2021. IR was 0.0025 (SE 0.0007, 95% CI 0.0013-0.0044), 0.0035 (SE 0.0007, 95% CI 0.0022-0.0053), 0.0028 (SE 0.0008, 95% CI 0.0015-0.0049), and 0.0052 (SE 0.0015, 95%CI 0.0027-0.0091) in the age groups <20 years, 20-44 years, 45-64 years, and 65+ years respectively. Incidence rate ratio (IRR) was 4.08 (95% CI 2.08 – 7.98) when comparing males and females, indicating that incidence rate in males was 4 times higher than in females. 65% of patients presented with advanced stage disease at the time of diagnosis. Median time from diagnosis to treatment was 13 days. mOS median overall survival was 101 months. The 1-year and 10- year CSS rates were 86%, and 68% respectively. mOS was 53 months for those with advanced stage disease at initial presentation. mOS was 17 months for ages >65 years (p=0.0002), compared to those aged less than 65 years. In Ann Arbor stage I disease, mOS was 144 months in patients < 65 years and 33.5 months in 65+ age group (p = 0.0157). In Ann Arbor stage IV disease, mOS was only 9 months in 65+ age group with p value of 0.0254 when comparing with the younger age group. There was no statistically significant difference in survival outcomes based on sex, and race. Summary/Conclusion This is one of the largest retrospective studies on ALK+ LBCL. We found that incidence of anaplastic lymphoma kinase-positive large B-cell lymphoma is more common in males and adults older than 65. Survival outcomes continue to be poor, especially in older adults. Further multicenter research is warranted to explore the genomic framework and discover novel combination therapies, to improve patient outcomes.
DOI: 10.1002/hem3.70152
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