Peripheral T-cell lymphoma: Are all patients high-risk?

Peripheral T-cell lymphomas (PTCL) are a heterogeneous group of mature T-cell neoplasms that represent approximately 10% of all non-Hodgkin Lymphoma (NHL). Outcomes for the majority of patients with PTCL are poor and treatment approaches have been relatively uniform using CHOP based therapy. For example, large registry studies consistently demonstrate 5-year overall survival (OS) of approximately 30-40%. However, as our understanding of the biology underpinning the heterogeneity of PTCL improves, and as treatments specifically for PTCL are developed, risk stratification has become a more relevant question. Tools including positron emission tomography-computed tomography (PET-CT) and minimal residual disease (MRD) monitoring offer the potential for dynamic risk stratification. In this review, we will first summarize registry data describing outcomes in the most common subtypes of PTCL - PTCL not otherwise specified (PTCL-NOS), nodal T-follicular helper cell lymphoma including angioimmunoblastic T-cell lymphoma (AITL), and anaplastic large cell lymphoma (ALCL). We will describe current clinically based prognostic indices validated in PTCL and then highlight emerging tools for prognostication including novel molecular biomarkers, imaging-based metrics, and MRD dynamics.