Survival Trends and Prognostic Modeling in ALK-Positive Anaplastic Large Cell Lymphoma: A Population-Based Study in the Brentuximab Vedotin Era.

[BACKGROUND] ALK-positive anaplastic large cell lymphoma (ALK+ ALCL) is a rare subtype of peripheral T-cell lymphoma with traditionally favorable prognosis. The introduction of brentuximab vedotin (BV) has significantly impacted treatment outcomes, but the long-term survival trends and predictive factors for this population remain underexplored.

[METHODS] A total of 1548 patients diagnosed with ALK+ ALCL between 2004 and 2017 were identified from the Surveillance, Epidemiology, and End Results (SEER) database. Patients were categorized into two eras: pre-BV (2004-2010, n = 795) and post-BV (2011-2017, n = 753). Overall survival (OS) was compared between eras. A random survival forest (RSF) model was constructed to identify prognostic factors and stratify survival risk in the post-BV cohort.

[RESULTS] OS significantly improved in the post-BV era (HR = 0.68, 95% CI: 0.58-0.81, p < 0.001), with the 5-year OS increasing from 59.3% to 72.3%. The RSF model identified age, Ann Arbor stage, primary site, B symptoms, and radiotherapy as key prognostic factors, showing good discrimination with C-indices of 0.775 (training cohort) and 0.728 (testing cohort). Notably, radiotherapy was found to be a protective factor. The model effectively stratified patients into high-risk (5-year OS: 49.3%) and low-risk (86.0%) groups.

[CONCLUSION] The introduction of BV has significantly improved real-world survival in ALK+ ALCL. The RSF model enables individualized risk stratification and may support future precision treatment strategies.