Consolidative Radiotherapy After Autologous Stem Cell Transplantation for Relapsed or Refractory Diffuse Large B-cell Lymphoma

Patients with relapsed or refractory diffuse large B-cell lymphoma undergoing autologous bone marrow transplantation benefited from consolidative involved-field radiotherapy (IFRT). All patients who underwent consolidative IFRT had improved locoregional control. Additionally, patients with enlarged lymphadenopathy had an improved locoregional control, disease-free survival, and overall survival at the 2-year evaluation. Introduction We evaluated the role of consolidative radiotherapy (RT) for patients undergoing high-dose chemotherapy (HDC) and autologous stem cell transplantation (ASCT) for relapsed or refractory diffuse large B-cell lymphoma (DLBCL). Materials and Methods We reviewed the medical records of 72 consecutive patients who had undergone ASCT for relapsed or refractory DLBCL at our institution from 2006 to 2014. Pretransplant conditioning consisted of HDC and total body irradiation. Of the 72 patients, 13 received post-transplant consolidative RT at the discretion of the consulted radiation oncologist. Results Consolidative RT was associated with significantly improved 2-year locoregional control (LRC) (92% vs. 68%; P =.04). However, no difference was seen in either the 2-year progression-free survival (PFS) (69% vs. 54%; P =.25) or overall survival (OS) (85% vs. 59%; P =.44). Analysis of the subgroup of 19 patients with persistent residual masses ≥ 2 cm on post-transplant imaging demonstrated a significant improvement in LRC (100% vs. 36%; P <.01), PFS (88% vs. 27%; P =.01), and OS (100% vs. 45%; P =.02) with consolidative RT. Conclusion The use of consolidative RT after HDC and ASCT for relapsed or refractory DLBCL appears to significantly improve LRC. For patients with masses ≥ 2 cm after ASCT, improved 2-year PFS and OS were seen. Prospective trials are needed to further identify the patients who would derive the most benefit from consolidative RT in the ASCT setting.