205 - 30Gy vs 40Gy Consolidative Radiotherapy for Limited-Stage Diffuse Large B cell Lymphoma Achieving Complete Remission after Chemotherapy: A Randomized, Open-Label, Non-Inferiority, Multicenter Phase 3 Clinical Trial
Presenter(s)
X. Liu1, T. WU2, Y. Shi3, Y. Zhang4, J. Shen5, H. Wang6, L. L. Zhang7, X. Ma8, X. Zhang9, H. Wang10, C. Hu11, W. Wang12, Y. LI13, and S. Qi14; 1Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences (CAMS) and Peking Union Medical College (PUMC), Beijing, China, 2Guizhou Cancer Hospital, Guiyang, China, 3Department of Radiation Oncology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China, 4sun yat sen university cancer hospital, guandzhou, Guangdong, China, 5Zhejiang Cancer Hospital, Hangzhou, China, 6The Affiliated Cancer Hospital of Zhengzhou University, Zhengzhou, China, 7Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China, Wuhan, China, 8Fudan University Shanghai Cancer Center, Shanghai, China, 9Department of Radiotherapy, Tianjin Medical University Cancer Institute and Hospital, Tianjin, China, 10Jiang Xi Province Cancer Hospital, Nanchang, China, 11Johns Hopkins University School of Medicine, Baltimore, MD, 12Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Radiation Oncology, Peking University Cancer Hospital & Institute, Beijing, China, 13Department 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, 14Radiation Oncology Department ,National Cancer Center, Cancer Hospital, Chinese Academy of Medical Sciences(CAMS) and Peking Union Medical College(PUMC), Beijing, China
Purpose/Objective(s):
Consolidative radiotherapy (RT) remains an important component in the management of limited-stage diffuse large B-cell lymphoma (DLBCL). However, the optimal consolidative RT dose remains undefined, with heterogeneous doses ranging from 30 to 55 Gy being used. To our knowledge, no randomized study has directly compared consolidative dose of 30 Gy versus 40 Gy in DLBCL patients. This study aimed to determine whether 30 Gy is non-inferior to 40 Gy in patients achieving complete remission (CR) following immunochemotherapy.Materials/Methods:
In this multicenter, non-inferiority, open-label, phase 3 trial, patients aged =15 years with newly diagnosed stage I-II DLBCL who achieved complete response (CR)/CRu after anthracycline-based chemotherapy with/without rituximab were randomly assigned (1:1) to 30 Gy or 40 Gy involved-site/field RT. The primary endpoint was 5-year progression-free survival (PFS).Results:
Between April 14, 2010, and July 1, 2019, 432 patients were enrolled and randomly assigned to the 40 Gy (n=216) or 30 Gy (n=216) group. A total of 213 in the 40 Gy group and 212 in the 30 Gy group were included in intention-to-treat analyses. After a median follow-up of 7.2 years, the 5-year PFS was 90.5% (95% CI 86.5–94.7) in the 30 Gy group and 87.2% (95% CI 82.7–91.9) in the 40 Gy group (hazard ratio 0.87; 95% CI 0.59–1.28; one-sided P = 0.0013 for non-inferiority). No significant differences were observed in overall survival or locoregional recurrence between groups. Subgroup analyses showed consistent treatment effects across prognostic factors. Acute and late toxicities, including second malignancies, were comparable between the two arms.Conclusion:
For patients with limited-stage DLBCL who achieve CR after chemotherapy, consolidative RT at 30 Gy provides non-inferior PFS compared with 40 Gy, with similar survival outcomes and toxicity profiles. These findings establish 30 Gy as a new standard of care in this setting, enabling reduced treatment intensity and potential long-term toxicity without compromising disease control.