Peripheral T-cell lymphomas: diagnosis and treatment options. Proceedings from a live roundtable, August 17, 2011, Kauai, Hawaii.

Peripheral T-cell lymphomas are a collection of rare diseases, most of which have a poor prognosis. The basic categories include precursor lymphoid neoplasms (eg, lymphoblastic lymphoma); mature natural killer/T-cell neoplasms and extranodal lymphomas, including enteropathy-associated T-cell lymphoma; hepatosplenic T-cell lymphoma; and subcutaneous panniculitis-like T-cell lymphoma. The most common varieties are the nodal types, which include peripheral T-cell lymphoma not otherwise specified, anaplastic large cell lymphomas, and angioimmunoblastic T-cell lymphomas. Each of the subtypes has characteristic clinical manifestations. The frequencies of the subtypes vary by geographic region. The diagnosis can be difficult, and the World Health Organization classification system was recently evaluated to assess its clinical applicability and reproducibility for peripheral T-cell lymphomas and natural killer/T-cell lymphomas. At least 10% of patients are incorrectly diagnosed by local laboratories, and many subtypes need better diagnostic markers and criteria. Currently, an increasing number of effective and tolerable therapies are becoming available, including pralatrexate, brentuximab vedotin, romidepsin, and bendamustine. Accurate diagnosis is necessary to allow appropriate treatment, as exemplified by patients with anaplastic large cell lymphoma that expresses high levels of CD30, who have high response rates to brentuximab vedotin. Patients with peripheral T-cell lymphoma should be enrolled in clinical trials when possible. New medications should be incorporated into therapies in well-designed clinical trials to develop appropriate safety and efficacy data.