Value of radiation therapy in the management of chemoresistant intermediate grade non-Hodgkin's lymphoma

The purpose of this study was to evaluate the probability and extent of res ponse to radiation therapy in patients with chemotherapy-resistant intermed iate grade non-Hodgkin's lymphoma. Thirty-five patients with chemotherapy-r esistant non-Hodgkin's lymphoma received local radiation therapy after Init ial treatment with at least six cycles of systemic chemotherapy. There were 17 men and 18 women in our study. Ages ranged from 15 to 68 years, median age was 42 years. Chemotherapy resistance was defined as relapse after init ial chemotherapy (11 patients) or failure to achieve complete remission (pa rtial response in 18 patients, stable disease in 1 patient, and disease pro gression in 5 patients). Radiation doses were between 1,980-5,040 cGy (medi an dose of 3,200 cGy). Treatment outcome was evaluated with respect to any subsequent relapse either within or outside the irradiated region. The 2-ye ar actuarial survival was 65%. The cumulative incidence of isolated local f ailure and any local failure at 2 years were 33% and 54%, respectively. Tum ors that responded to initial chemotherapy had a better local control proba bility than tumors that did not respond. The 2-year actuarial local failure rates for these two groups were 51% and 83%, respectively (P = 0.01). Ther e was a trend for improved local control with radiation doses greater than or equal to 3,960 cGy, suggesting the presence of a dose-control relationsh ip. The rate of disease progression within an irradiated region in patients with intermediate grade non-Hodgkin's lymphoma that relapsed after or fail ed to respond completely to full course chemotherapy was substantially high er than the historical in-field failure rates when radiation therapy was us ed as the sole modality of treatment. Prior response to initial chemotherap y was a predicting factor for local control following radiation therapy. (C ) 1999 Wiley-Liss, Inc.