Radiation therapy after a partial response to chop chemotherapy for aggressive lymphomas

Purpose: To analyze the results with involved-field radiotherapy after aggr essive Lymphomas had decreased in size by 50-99% in response to cyclophosph amide, doxorubicin, vincristine, and prednisone (CHOP)-based chemotherapy. Methods and Materials: From 1988 through 1996, 294 previously untreated pat ients with Working Formulation intermediate-grade or large-cell immunoblast ic lymphomas underwent CHOP-based chemotherapy on 2 consecutive protocols a t the M, D, Anderson Cancer Center, Forty-four (15%) of these patients achi eved, based on international working group guidelines, a partial (50-75%) r esponse (n = 25), or unconfirmed complete (76-99%) response (n = 19) to a m edian of 6 cycles of chemotherapy. These patients were treated with salvage involved-field radiotherapy (n = 32) or chemotherapy (n = 12), e,g,, MINE- ESHAP, without autologous stem-cell rescue (ASCR), Results: Median follow-u p was 43 months, Partial responders experienced similar outcomes to unconfi rmed complete responders. Local control (4-year rates: 86% vs, 53%,p = 0.00 9) and progression-free survival (4-year rates: 67% vs. 8%,p < 0.0001), but not overall survival (4-year rates: 70% vs. 50%,p = 0.067) were significan tly better in those who received salvage radiotherapy, which was well toler ated. Conclusion: Progression-free and overall survival in aggressive lymph oma patients who underwent salvage radiotherapy were similar to results rep orted for high-dose chemotherapy with ASCR, The role of salvage radiotherap y in partial and unconfirmed complete responders to CHOP chemotherapy justi fies examination in a large, cooperative group trial. (C) 2001 Elsevier Sci ence Inc.