Impact of Radiation Therapy After High Dose Chemotherapy and Autologous Hematopoietic Stem Cell Transplantation in Patients With Relapsed/Refractory Lymphomas: A Single Center Experience.

Introduction: After high dose chemotherapy (HDC) and autologous stem cell transplantation (auto-SCT), in patients with relapsed/refractory diffuse large B cell lymphoma (DLBCL) and Hodgkin lymphoma (HL), involved field radiation therapy (RT) for consolidation and residual/progressive disease (PD) eradication is a common practice.

Materials And Methods: Retrospective single-institution cohort analysis to evaluate the impact of early RT after HDC auto-SCT.

Results: Between 1996 and October 2019, 153 patients (43 DLBCL, 110 HL) underwent RT after HDC auto-SCT. Males 95 (62%), females 58 (38%), median age 24 years. Indications for RT was consolidation 65%: residual disease eradication 16%: and PD eradication 19%. For DLBCL, the median overall survival (OS) for the above indications was not reached (NR):NR:2 months and the KM 5-year OS was 72.6%:64.3%:12.5% respectively (P ≤ .000). Pair-wise analysis showed that consolidation versus residual disease eradication had no difference (P = .88) but both were superior to PD disease eradication (P ≤ 000 and P = .005 respectively). For HL, indication for RT was, 54%:23%:24% respectively. The median OS was NR:NR:28.8 months and KM 5-year OS was 82.3%:78%:30% respectively (P ≤ .000). Pair-wise analysis showed that consolidation versus residual disease eradication had no difference (P = .98) but both were superior to the PD eradication group (P ≤ 000). RT was well tolerated with no significant long-term toxicity.

Conclusion: Post HDC auto-SCT RT was well tolerated. DLBCL and HL patients with residual disease treated with the RT had similar long-term survival as those who received RT for consolidation. RT failed to improve the poor survival in patients with post-HDC auto-SCT PD.