Prevention and treatment of central nervous system involvement by non-Hodgkin's lymphoma: a review of the literature.

Direct invasion of the central nervous system (CNS) occurs in 5% of all patients with non-Hodgkin's lymphoma, either at the time of presentation, as a solitary site of relapse, or during the course of progressive disease. Over the last several years, several studies, mostly retrospective, have analyzed risk factors associated with this complication as well as various methods to both treat and prevent it. A systematic review of the literature reveals that although a profile of a patient at particularly high risk for developing disease can be identified, treatments are for the most part ineffective at improving survival in patients with CNS lymphoma, and there is no high-quality evidence that prophylaxis prevents its occurrence. A randomized controlled trial to assess the value of prophylaxis in this disease is warranted, and suggestions for how such a trial might be designed are included in this review.