Analysis of Peripheral T-Cell Lymphoma Diagnostic Work-Up in the United States

Abstract Background With increased understanding of unique entities, subtype specific approaches for peripheral T-cell lymphomas (PTCL) are emerging and more precise diagnoses is becoming increasingly important. Methods We analyzed the approach to the histopathological diagnosis PTCL using data from the Comprehensive Oncology Measures of Peripheral T-cell Lymphoma (COMPLETE) study. COMPLETE is a large prospective cohort study of newly diagnosed PTCL patients in the United States. Results A total of 499 patients were enrolled from 40 academic and 15 community-based centers. Baseline assessment forms were collected for 493 patients, of which 435 (88%) were available for analysis. The most common diagnoses were: PTCL-not otherwise specified (PTCL-NOS), anaplastic large cell lymphoma (ALCL), and angioimmunoblastic T-cell lymphoma (AITL). A mean of 10 markers (range: 0-21) was assessed per patient. CD30 was assessed frequently but not uniformly in non-ALCL cases. Only 17% of PTCL-NOS cases were assessed for PD1. CXCL13 was a relatively sensitive marker in AITL, being expressed in 84% of tested cases; however, only 3% of PTCL-NOS cases were tested. T follicular helper marker assessment differed between academic and community practices, with PD1 more often evaluated by academic centers in AITL (62% vs. 12%; p=0.01). Conclusion The diagnostic work-up for PTCL in the US is widely variable, often lacking important phenotypic information to fully characterize the lymphoma. Gaps in testing of selected markers will need to be filled given the impending revision to the WHO classification. Accuracy of diagnosis will become increasingly important as we enter the era of targeted treatment for PTCL.