Preface

Non-Hodgkin's lymphomas are a heterogeneous group of more than 60 entities that differ in morphology, genetics, immunology, clinical features, and outcome following therapy. Newer technologies, such as DNA microarray analyses, have demonstrated that tumors with a similar appearance under the microscope may have markedly distinct gene expression profiles, which are associated with a different clinical course. We also have learned that a lymphoma's microenvironment, characterized by lymphoma-associated macrophages, regulatory T cells, and a variety of cytokines, plays a major role in the behavior of lymphomas.

Importantly, over the past decade, major progress has been made in therapeutic approaches and the manner in which response to treatment is measured. The availability of clinically effective and well-tolerated monoclonal antibodies has improved the survival of patients who have indolent and aggressive lymphomas. Unfortunately, curative strategies remain elusive for indolent histologies and mantle cell lymphoma. New agents targeting novel pathways or influencing the host or tumor immunologic status are in clinical trials and may improve patient outcome. However, the optimal use of antibodies and other targeted agents remains to be defined. Staging and response assessment traditionally relied on physical examination and CT scans. The availability of metabolic imaging studies, especially 18F-fluoro-2-deoxy-D-glucose positron emission tomography, has the potential to alter staging, prognosis, and assessment of response. The larger role for this technology may be used in risk-directed therapeutic strategies leading to an improvement in patient outcome, by modifying therapy early in nonresponsive patients, or used to reduce treatment-related toxicities by limiting the amount of therapy required in responding patients. Traditional prognostic schemes are being revised to incorporate clinically relevant biomarkers with the goal of individualizing therapy.

Each of the authors of the various articles in the current Hematology/Oncology Clinics of North America has made major contributions to the understanding of non-Hodgkin's lymphomas and to the development of newer and more effective treatments. I hope this volume will convince the practicing hematologist/oncologist and the clinical researcher that enormous progress has been made in the treatment of non-Hodgkin's lymphomas. However, continued progress requires a dedication to high quality clinical research trials.