The risk of central nervous system relapses in patients with peripheral T-cell lymphoma

We performed a retrospective analysis to identify risk factors and survival outcome for central nervous system (CNS) relapse of peripheral T-cell lymphoma (PTCL) by histologic type. Records of 600 PTCL patients diagnosed between 1999 and 2014 were analyzed including PTCL not otherwise specified (PTCL-NOS, 174 patients), angoimmunoblastic T-cell lymphoma (AITL, 144), ALK+anaplastic large cell lymphoma (ALCL, 74), ALK-ALCL (103), extranodal NK-cell lymphoma (ENKL, 54), or others (51). With a median follow up of 57 months, 13 patients (4 PTCL-NOS, 1 AITL, 4 ALK+ALCL, 2 ALK-ALCL, 2 ENKL) experienced CNS relapse. One-year and 5-year cumulative incidence of CNS relapse were 1.5% (95%CI: 0.7-2.8%) and 2.1% (95%CI: 1.1-3.5%), respectively. The 5-year cumulative incidence of CNS relapse was 1.8% in PTCL-NOS, 0.7% in AITL, 5.4% in ALK+ALCL, 2.1% in ALK-ALCL and 3.7% in ENKL. Extranodal involvement >1 site was the only significant factor associated with higher chance of CNS relapse (HR: 4.9, 95%CI: 1.6-15.0, p = 0.005). Patients with ALK+ALCL who had extranodal involvement >1 (N = 19) had very high risk of CNS relapse with one year cumulative incidence of 17% (95%CI: 4%-37%), all occurring within six months after diagnosis. All patients with CNS relapse eventually died (median, 1.5 months; range, 0.1-10.1 months). CNS relapse in patients with PTCL is rare event but the risk varies by subtype. ALK+ALCL patients with extranodal involvement >1 site have a very high risk of early CNS relapse, and thus evaluation of CNS involvement at the time of diagnosis and possible CNS-directed prophylaxis may be considered.