LAUSR

Introduction Peri-transplant radiation (XRT) in Hodgkin Lymphoma (HL) patients undergoing autologous stem cell transplant (ASCT) has been associated with improved local control. However, this has not been well established with increased use of novel agents in peri-transplant setting. Methods This was a retrospective analysis of HL patients who underwent their first ASCT between 2000 and 2018 at Karmanos Cancer Institute. Peri-transplant radiation was defined as XRT within 3-month window of ASCT. Novel agents included brentuximab, check-point inhibitors (CIs), and other targeted agents. The primary endpoint was to compare overall survival (OS) based on utilization of peri-transplant XRT and novel agents with standard salvage chemotherapy. Results From 2000-2018, there were total of 220 patients who underwent ASCT for HL. Peri-transplant XRT was used in 30 (14%) patients and was utilized similarly in patients who had ASCT before or after 2010 (13% vs 14%); novel salvage was used in 32 (15%) patients before transplant (Figure 1). There was no difference in baseline characteristics (bulky relapse, local vs systemic relapse, etc.) of patients who did or did not receive peri-transplant XRT (Table 1). Median OS of all the patients who had ASCT was 11 years [7.6-NR]. Median OS of patients who had peri-transplant XRT was not reached [9.4-NR] compared to 7.7 [5.3-NR] years for those without peri-transplant XRT [HR 0.38; 95% CI 0.15-0.96; p=0.033] (Figure 2). Median OS of patients who had novel salvage was not reached [4.3-NR] compared to 11 [7.6-NR] years for those without novel salvage [HR 1.08; 95% CI 0.43-2.72; p=0.877]. Median OS of patients who had either novel salvage or peri-transplant XRT was not reached [9.4-NR] compared to 11 years [6.5-NR] for those who had chemotherapy salvage only [HR 0.64; 95% CI 0.32-1.26; p=0.193]. In the multivariable analysis, less than CR to salvage therapy and lack of peri-transplant XRT use were associated with worse OS.There were total of 85 (39%) patients who progressed after ASCT. Median OS for those patients was 3.5 years [2.3-8.8]. In addition, the median OS for patients who received novel agent at any time after transplant was 6.9 years [2.6-NR] after relapse from ASCT compared to 2.5 years [2.2-7] for those who did not [HR 1.96; 95% CI 1-3.86; p=0.048] (Figure 3). Conclusions Peri-transplant XRT was possibly used in patients who had residual disease or other high-risk features that could not be identified due to retrospective nature of this study and, despite this, use of peri-transplant XRT was associated with modest survival benefit. Surprisingly, use of novel agents during salvage was not associated with survival benefit. Utilization of novel agents at any time after post-transplant progression was associated with OS benefit.