Non-Hodgkin lymphoma: Diagnosis and treatment

Non-Hodgkin lymphomas are a heterogeneous group of malignancies of the lymphoid system. Based on the World Health Organization classification of hematological and lymphoid tumors, these diseases have been classified as B-cell and T-cell neoplasms. B-cell lymphomas account for approximately 90% of all lymphomas, and the 2 most common histological disease entities are follicular lymphoma and diffuse large B-cell lymphoma. Approximately 55,000 to 60,000 new cases of non-Hodgkin lymphoma are diagnosed annually in the United States, a number that has nearly doubled during the past 3 decades. The Ann Arbor Staging Classification is used routinely to classify the extent of disease, and the International Prognostic Index has been used to define prognostic subgroups. Also, recent data have identified molecular and genetic markers of prognosis that may be used in the future to further refine treatment decisions. Treatment of these diseases is based on the histology and extent of disease. Patients with follicular lymphomas with early-stage disease generally are treated with radiation therapy, whereas those with stage III and IV disease requiring treatment usually are treated with chemotherapy, immunotherapy, or radioimmunotherapy. These patients generally experience long survival, but only a minority are cured. For patients with diffuse large B-cell lymphoma, treatment of limited-stage disease generally includes doxorubicin-based chemotherapy combined with rituximab followed by involved field radiation therapy. Those with extensive disease are treated with rituximab combined with chemotherapy alone. Disease relapse is a problem, and high-dose therapy with stem cell support is the treatment of choice for chemosensitive relapsed aggressive lymphomas. Patients with chemoresistant disease or whose disease relapses subsequently should be treated with novel experimental therapies.