2791 - Immune Checkpoint Inhibitor Combined with Radiotherapy for Relapsed/Refractory Classical Hodgkin Lymphoma: A Transplant-Free Retrospective Study
Presenter(s)
Y. Liu, X. Liu, S. Qi, and Y. LI; Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
Purpose/Objective(s): High-dose chemotherapy and autologous stem cell transplantation is the standard treatment for relapsed or refractory classical Hodgkin lymphoma (R/R cHL) at the pay of high toxicities. Given the promising activity of immune checkpoint inhibitors (ICIs) alone or with chemotherapy in R/R settings and the high gross tumor control with radiotherapy (RT), their combination may offer an effective salvage option in selected cases, to replace transplantation. This study evaluated the efficacy and safety of this combination in selected patients with R/R cHL.
Materials/Methods: We retrospectively screened patients with R/R cHLs treated at a single institution between 2018 and 2024. Patients received combined salvage treatment with ICIs (± chemotherapy) and RT, administered either concurrently or sequentially (interval =3 months) were eligible for current analysis. The treatment outcomes were analyzed according to clinical factors, and toxicities were displayed.
Results: Overall, 28 patients were included. 22 patients (78.6%) received ABVD as first-line chemotherapy. After that, 18 patients (64.3%) were primary refractory, and 10 patients (35.7%) relapsed with a median interval of 19.6 months (IQR 4.5-47.0). After R/R cHL diagnosis, 10 patients (35.7%) received immune checkpoint inhibitors (ICIs) as monotherapy with a median of 8 doses, while the remaining patients received ICI-based combination therapies with a median of 6 cycles, including 13 with chemotherapy and 5 with BV. All patients were treated using modern RT techniques, including volumetric modulated arc therapy (VMAT; n = 23, 82.1%) and tomotherapy (n = 5, 17.9%). 18 patients (64.3%) had RT fields encompassing all involved sites from initial diagnosis to current recurrence, 7 patients (25.0%) received RT field encompassing only relapse/refractory sites, and 3 patients (10.7%) received RT field encompassing only PET-positive residual sites before RT. The median dose to the clinical tumor volume was 30 Gy (IQR, 30 - 30), delivered in a median of 15 fractions (IQR, 12.5 - 15) at 1.8 - 3.0 Gy per fraction. Eight patients (28.6%) received an additional simultaneous integrated boost to the gross tumor volume, with a median dose of 8.75 Gy (IQR, 7.9 - 10.2). After a median follow-up of 36.5 months (range, 4.1–75.4 months), the estimated 3-year progression-free survival (PFS) and overall survival (OS) rates were 79.6% and 100%, respectively. Six patients (21.4%) experienced disease relapse, all occurring outside the irradiated fields, and no deaths were observed. PFS was associated with stage IV disease (P < 0.001) and GHSG prognostic score for r/r HL (P < 0.001). Treatment was well tolerated, with no grade =3 radiation-related adverse events recorded during radiation.
Conclusion: Immunotherapy combined with RT achieved high rates of durable disease control in selected patients with R/R cHL and may serve as a viable salvage treatment option. Further studies are needed to refine patient selection and optimize treatment strategies.