Mature T-cell malignancies: a diagnostic and therapeutic challenge
Peripheral T-/NK-cell lymphomas/leukaemias (PTCL/L) comprise a heterogeneous group of haematopoietic tumours, which originate from mature T-/NK-cells, and constitute less than 15% of all non-Hodgkin lymphomas (NHL) in adults of the Western hemisphere. These neoplasms often present at advanced stage at the time of diagnosis, and most commonly have an aggressive clinical course requiring prompt treatment. In contrast to B-cell NHL, in which substantial clinical progress has been made with the introduction of monoclonal antibodies such as Rituximab, no comparable advances have been seen in PTCL/L. Moreover, no PTCL/L standard therapies have been established so far, and most PTCL/L have been treated in analogy to B-cell NHL. However, for PTCL/L these adapted protocols generally result in a much lower efficacy along with frequent relapses. Approximately 30% of PTCL/L even show a primary refractory behaviour. In this review, the diagnostic features of the most common entities of PTCL/L and a proposed workup are presented. Moreover, currently applied therapeutic strategies like conventional chemotherapy or high-dose therapy as well as new drugs like histone deacetlyase inhibitors or immune modulatory reagents are discussed. We once more conclude that as no efficient standard therapy has been established for most PTCL/L subtypes, treating patients with PTCL/L in clinical trials is strongly recommended.