High-dose therapy and transplantation in non-Hodgkin's lymphoma.

High-dose therapy and transplantation have been explored as a therapeutic option for patients with non-Hodgkin's lymphomas (NHLs) for the past two decades, in an effort to improve the long-term outcome of this spectrum of disorders. Although a plethora of pilot and phase II studies in the various subtypes of NHL have been reported, there is a problematic lack of randomized phase III trials that would aid in answering important questions regarding the role of transplantation in these disease processes. The results of transplantation trials for these patients are also confounded by the relatively short follow-up intervals in low-grade NHL and small patient numbers in studies of transplantation for less common NHL subtypes, such as lymphoblastic, Burkitt's, and mantle cell lymphomas. The emerging late toxicities of transplantation are of increasing concern and underscore the need for more studies that address questions of relative therapeutic benefits. Fortunately, the limitations of these existing studies are recognized, and new transplantation trials presently underway or in development are beginning to address these concerns. As clinical transplantation moves into a more mature phase, these phase III studies should provide more definitive answers as to the specific role of transplantation in specific subtypes of NHL.