[Central nervous system relapse in diffuse large B cell lymphoma: Risk factors].

Central nervous system (CNS) involvement by lymphoma is a complication associated, almost invariably, with a poor prognosis. The knowledge of the risk factors for CNS relapse is important to determine which patients could benefit from prophylaxis. Thus, patients with very aggressive lymphomas (such as lymphoblastic lymphoma or Burkitt's lymphoma) must systematically receive CNS prophylaxis due to a high CNS relapse rate (25-30%), while in patients with indolent lymphoma (such as follicular lymphoma or marginal lymphoma) prophylaxis is unnecessary. However, the question about CNS prophylaxis in patients with diffuse large B-cell lymphoma (DLBCL), the most common type of lymphoma, remains controversial. The information available is extensive, mainly based on retrospective and heterogeneous studies. There seems that immunochemotherapy based on rituximab reduces the CNS relapse rate. On the other hand, patients with increased serum lactate dehydrogenase plus more than one extranodal involvement seem to have a higher risk of CNS relapse, but a prophylaxis strategy based only on the presence of these 2 factors does not prevent all CNS relapses. Patients with involvement of testes or breast have high risk of CNS relapse and prophylaxis is mandatory. Finally, CNS prophylaxis could be considered in patients with DLBCL and renal or epidural space involvement, as well as in those cases with MYC rearrangements, although additional studies are necessary.