The place of radiation therapy in the treatment of non-Hodgkin's lymphomas.

The use of Hodgkin's disease as a model for the evaluation and management of the non-Hodgkin's lymphomas may not be appropriate. This latter group of different syndromes and diseases differs significantly in their clinical presentation from each other as well as from Hodgkin's disease. Survival must be separated from relapse-free survival since the latter is a measure of the effectiveness of any individual therapy being applied. Localized nodal lymphoma is uncommon, but important to identify since it is potentially curable by irradiation. Stage I nodular, non-histiocytic lymphomas treated by radiation results in significant, extended, relapse-free survival. All other localized nodal lymphoma is associated with a high proportion of patients relapsing outside the treatment portal. Whole body irradiation is a useful systemic agent causing regression for an extended period of time in stage III or stage IV nodular lymphoma. Chemotherapy seems to have a limited value in nodular lymphomas, with no clear evidence that combination chemotherapy is more effective than single agents. In diffuse lymphomas, aggressive chemotherapy shows more promise, with diffuse histiocytic lymphoma having extended relapse-free survival.