Localized large cell lymphoma: is there any need for radiation therapy?

Diffuse large B-cell lymphoma is the most common lymphoma diagnosed in the United States and presents as localized disease in about 25% of the patients. The standard of care was established by Southwest Oncology Group trial 8736, which showed the superiority of a short course of chemotherapy followed by radiation over a longer course of chemotherapy alone. This review discusses the studies that followed with the intent to establish whether the standard of care has changed.

Subsequent studies examined the role of radiation therapy, the number of cycles and intensity of chemotherapy, and addition of rituximab. Interpretation of results has been confounded by patient selection, especially by including patients with bulky stage II disease. Quality of radiation therapy may have diminished its efficacy in some of the studies. Concurrent administration of rituximab provided a more modest improvement as compared with advanced disease setting. Attempts are now made to use PET scans to eliminate the need for radiation therapy in some patients.

Radiation therapy remains useful when administered expediently and as initially described, but PET scans successfully define a subset of patients who do not benefit from radiation. Using a longer or more intensive course of rituximab-containing chemotherapy without radiation has never been compared to combined modality treatment and remains investigational.