Patterns of failure in advanced-stage diffuse large B-cell lymphoma (DLBCL) patients treated with R-CHOP chemotherapy and the emerging role of consolidative radiotherapy.

Abstract

8546 Background: The role of consolidative radiotherapy (RT) after a complete response (CR) to R-CHOP for stage III-IV DLBCL patients is unclear. The goal of our study is to evaluate the Emory experience when consolidative RT is delivered to initial presenting nodal and extranodal sites or bulky sites in these patients. Methods: From 01/2000 to 05/2012, 211 histologically confirmed DLBCL patients with stage III-IV disease who received R-CHOP were identified at Emory University. Patterns of failure for patients who achieved CR to R-CHOP were analyzed. Local control (LC), distant control (DC), progression free survival (PFS) and overall survival (OS) were estimated using Kaplan-Meier method and compared between patients who received R-CHOP alone versus R-CHOP plus consolidative RT using Log-rank test. Multivariate analyses were also performed using Cox proportional hazards model. Results: 163 patients had detailed treatment records. After a median 6 cycles of R-CHOP, 110 patients (67.5%) achieved CR and were entered for analysis. Fourteen patients (12.7%) received consolidative RT to a median dose of 30.6 Gy as part of initial management. With a median follow up time of 32.9 months, 43.8% of patients who received R-CHOP alone failed at the initial presenting sites with or without distant recurrence (DR), whereas isolated DR only occurred in 3.2% of these patients. Consolidative RT was associated with significantly improved LC (91.7% vs 48.8%, p<0.0001), DC (92.9% vs 71.9%, p<0.0001), PFS (85.1% vs 44.2%, p<0.0001) and OS (92.3% vs 68.5%, p<0.0001) at 5-years when compared to patients with R-CHOP alone. In addition, the in-field control rate was 100% within irradiated sites for patients who received consolidative RT. On multivariate analysis, consolidative RT and non-bulky disease were predictive of increased LC and PFS, whereas bone marrow involvement was associated with increased risk of DR and worse OS. Conclusions: 44% of patients with advanced stage DLBCL failed at initial presenting sites despite achieving a CR to R-CHOP. Incorporation of consolidative RT as part of upfront treatment in these patients was associated with improved LC and PFS.