The Risk of Central Nervous System (CNS) Relapses in Patients with Peripheral T-Cell Lymphoma
Authors: Chihara Dai , Fanale Michelle A , Miranda Roberto N. , Noorani Mansoor , Westin Jason R. , Nastoupil Loretta J. , Hagemeister Fredrick B. , Fayad Luis E. , Romaguera Jorge E. , Samaniego Felipe , Turturro Francesco , Lee Hun Ju , Neelapu Sattva S. , Rodriguez Alma , Wang Michael , Fowler Nathan , Medeiros L. Jeffrey , Davis Richard Eric , Oki Yasuhiro 
Published: October 2019

Abstract
Background: CNS relapse is a rare but fatal complication of patients with peripheral T-cell lymphoma (PTCL). Several large studies have identified risk factors for CNS relapse in PTCL, such as elevated serum lactate dehydrogenase (LDH), >1 extranodal sites of involvement and high International Prognostic Index (IPI) score. We performed an analysis of histologic type of PTCL to identify additional risk factors for CNS relapse.
Patients and Methods: A total of 616 patients with PTCL diagnosed between 1999 and 2014 were analyzed retrospectively including: 174 not otherwise specified (NOS), 144 angoimmunoblastic T-cell lymphoma (AITL), 76 ALK+ anaplastic large cell lymphoma (ALCL), 103 ALK-ALCL, 55 nasal type T/NK cell lymphoma (NK/T), 23 hepatopslenic T-cell lymphoma (HSTL), 16 enteropathy-type T-cell lymphoma (EATL), 13 adult T-cell leukemia/lymphoma (ATLL), and 12 subcutaneous panniculitis-like T-cell lymphoma (SPTL). Patients with CNS involvement at diagnosis (n=15) were excluded from this study. Progression-free survival (PFS) and overall survival (OS) were calculated and pretreatment characteristics were evaluated for association with survival outcomes by hazard ratio (HR). Cumulative incidence of CNS relapse was calculated by competing risk (death without CNS relapse) regression analysis.
Results: The median age of the patients was 56 years (range, 17-93 years). With a median follow up of 57 months, 15 patients (4 PTCL-NOS, 1 AITL, 4 ALK+ALCL, 2 ALK-ALCL, 2 NK/T, and 2 ATLL) experienced CNS relapse, and 321 patients (52%) died without having had CNS relapse. One-year and 5-year cumulative incidence of CNS relapse were 1.8% (95%CI: 1.0-3.1%), 2.4% (95%CI: 1.3-3.8%), respectively. The 5-year cumulative incidence of CNS relapse was 1.8% in PTCL-NOS, 0.7% in AITL, 5.3% in ALK+ALCL, 2.1% in ALK-ALCL and 3.6% in NK/T (Figure). All patients with CNS relapse eventually died, with median OS duration from CNS relapse of 1.6 months. Extranodal sites of involvement >1 (HR: 6.0, 95%CI: 2.0-17.4) and higher IPI score (HR: 1.8, 95%CI: 1.1-3.1, by one increase in IPI score) were risk factors of CNS relapse by univariate analysis. ALK+ALCL patients who had > 1 extranodal site of involvement (N=19) had very high risk of CNS relapse with one year cumulative incidence of 15% (95%CI: 3.7%-33.5%), with all occurring within six months after diagnosis.
Summary: CNS relapse in patients with PTCL is rare as reported previously. However, the risk varies by histologic type. Specifically ALK+ALCL patients with > 1 extranodal site of involvement have a very high risk of CNS relapse in early phase of treatment, and CNS evaluation at the time of diagnosis and possibly CNS targeted prophylaxis may be appropriate.
Figure Figure.

Disclosures
Westin: ProNAi: Membership on an entity's Board of Directors or advisory committees; Chugai: Membership on an entity's Board of Directors or advisory committees; Spectrum: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Fayad:Seattle Genetics: Consultancy, Research Funding. Wang:BeiGene: Research Funding; Kite Pharma: Research Funding; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Asana BioSciences: Research Funding; Dava Oncology: Honoraria; Asana biosciences, Beigene, Celgene, Juno, Kite, Onyx, Pharmacyclics: Research Funding; Acerta: Consultancy, Research Funding; Juno Therapeutics: Research Funding. Fowler:Roche: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Jannsen: Consultancy, Research Funding; Gilead: Research Funding; Infinity: Consultancy, Research Funding; TG Therapeutics: Consultancy. Oki:Novartis: Research Funding.