Peripheral T-cell lymphomas (PTCLs) comprise a heterogeneous group of neoplasms that are derived from post-thymic lymphoid cells at different stages of differentiation with different morphological patterns, phenotypes, and clinical presentations. PTCLs are highly diverse, reflecting the diverse cells from which they can originate. Peripheral T-Cell Lymphomas account for 5-10% of all lymphoproliferative disorders in the Western hemisphere, with an overall incidence of 0.5-2 per 100,000 per year, and have a striking epidemiological distribution, with higher incidence in Asia.

The clinical features of PTCLs are extremely heterogeneous. PTCLs express even more clinical diversity than B-cell NHLs, and there is a close, though not absolute, relationship between some unusual clinical features and certain histological subtypes. Despite efforts to transferring to patients with T-cell lymphomas the most recent advances in the treatment of other subtypes of B-cell lymphomas, the prognosis of patients with PTCL is still poor an, unfortunately, the optimal therapy for PTCL is still unknown. The complete response rate is rather low, ranging from 40% to 50% with a median Relapse Free Survival (RFS) of 2-3 years. As a consequence of the aggressiveness of the disease and of the low efficacy of available salvage treatments, Overall Survival (OS) is also short and the long-term survival rate is lower than 10% in many series.

To better define the clinical outcome of PTCL-NOS, the Intergruppo Italiano Linfomi (IIL, now Fondazione Italiana Linfomi, FIL) performed a large study on 385 patients diagnosed and treated in the 1990s and defined a prognostic model specifically devised for patients with this uncommon disease (Gallamini, A. et al Blood, 2004. 103(7): p. 2474-9). In addition to defining a prognostic model specifically devised for PTCL-NOS, the FIL study confirms the relevance of research on series of clearly defined cases in order to the development of rationally designed and potentially more-efficacious treatment modalities. More recently, the role of biological features of the disease is emerging as an important issue not only for understanding its pathogenesis but also for prognosis and for addressing specific biologic targets altered in the neoplasia. Significant progress in the prognosis of PTCL can be expected from the novel, sophisticated, and powerful technologies of genomics and proteomics, which will allow more reliable subtyping of PTCL into distinct clinical groups characterized by different patterns of survival, as already demonstrated for some B-NHLs.

One common limitation of existing studies on prognosis of PTCL is their retrospective nature. Currently available data are based on analysis performed on series collected over a long period of time. This aspect is very important as it may introduce relevant biases in the collected series. First classification systems have changed dramatically over time and cases may have been defined in differently based on diagnosis year. Second some clinical or laboratory data which now are considered as prognostic relevant may have not been determined in older series of patients. Third in a retrospective analysis there is no guarantee that collected series are based on real consecutive cases. These are the reasons why we thought it would be useful to start a new study based on the prospective registration in a short period of time of patients with diagnosis of Peripheral T-cell lymphoma for whom it would be possible collect an exhaustive set of clinical data and biological information.