Prognostic Factors and Outcomes of Adult Lymphoblastic Lymphoma in the United States.

Background: T-lymphoblastic lymphoma (T-LL) and B-lymphoblastic lymphoma (B-LL) are aggressive lymphoid neoplasms accounting for 2% to 4% of adult non-Hodgkin lymphoma. The aim of the present analysis was to characterize the clinical features and histologic subtypes and to assess the clinical prognostic factors for 696 adult patients with LL, the largest epidemiologic sample to date.

Patients And Methods: The present retrospective cohort study used the Surveillance, Epidemiology, and End Results database to identify adult patients (age, > 18 years) with LL with data recorded from 2001 to 2012. We used multivariate Cox regression models to test the clinical prognostic factors, stratified by the histologic subtype.

Results: Of 696 patients with LL (median age, 39 years), 367 (53%) had T-LL and 131 (19%) had B-LL. Patients with T-LL tended to be younger (33 years vs. 48 years), male (66% vs. 50.4%), and less likely to have extranodal involvement (6% vs. 32%) compared with those with B-LL. The 5-year survival rate for those with B-LL versus those with T-LL was not significantly different (45% vs. 48%; P = .58), even in a model adjusted for clinical features, disease stage, primary site, radiotherapy, and year of diagnosis (adjusted hazard ratio, 0.93; 95% confidence interval, 0.69-1.25; P = .63). Multivariate analysis identified age, race, and radiotherapy as independent prognostic factors for outcome in T-LL. Limited tumor stage and the most recent year of diagnosis were favorable prognostic factors for B-LL.

Conclusion: Adult patients with LL have poor long-term outcomes and novel therapies are needed. Radiotherapy had a positive effect on T-LL outcomes.