Additional survival benefit of involved-lesion radiation therapy after R-CHOP chemotherapy in limited stage diffuse large B-cell lymphoma

Abstract

Purpose: The purpose of this study was to evaluate the role of involved-lesion radiation therapy (ILRT) after rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) chemotherapy in limited stage diffuse large B-cell lymphoma (DLBCL) by comparing outcomes of R-CHOP therapy alone with R-CHOP followed by ILRT. Methods and Materials: We identified 198 patients treated with R-CHOP (median, 6 cycles) for pathologically confirmed DLBCL of limited stage from July 2004 to December 2012. Clinical characteristics of these patients were 33% with stage I and 66.7% with stage II; 79.8% were in the low or low-intermediate risk group; 13.6% had B symptoms; 29.8% had bulky tumors (>= 7 cm); and 75.3% underwent >= 6 cycles of R-CHOP therapy. RT was given to 43 patients (21.7%) using ILRT technique, which included the prechemotherapy tumor volume with a median margin of 2 cm (median RT dose: 36 Gy). Results: After a median follow-up of 40 months, 3-year progression-free survival (PFS) and overall survival (OS) were 85.8% and 88.9%, respectively. Multivariate analysis showed >= 6 cycles of R-CHOP (PFS, P = .004; OS, P = .004) and ILRT (PFS, P = .021; OS, P = .014) were favorable prognosticators of PFS and OS. A bulky tumor (P = .027) and response to R-CHOP (P = .012) were also found to be independent factors of OS. In subgroup analysis, the effect of ILRT was prominent in patients with a bulky tumor (PFS, P = .014; OS, P = .030) or an elevated level of serum lactate dehydrogenase (LDH; PFS, P = .004; OS, P = .012). Conclusions: Our results suggest that ILRT after R-CHOP therapy improves PFS and OS in patients with limited stage DLBCL, especially in those with bulky disease or an elevated serum LDH level. (C) 2015 Published by Elsevier Inc.