Role of radiotherapy in treatment of extramedullary relapse following total marrow and lymphoid irradiation in high-risk and/or relapsed/refractory acute leukemia

• Authors: Colton Ladbury, City of Hope National Medical Center; Hemal Semwal, University of California Los Angeles; Daniel Hong, Emory University; Dongyun Yang, City of Hope National Medical Center; Claire Hao, City of Hope National Medical Center; Chunhui Han, City of Hope National Medical Center; An Liu, City of Hope National Medical Center; Guido Marcucci, City of Hope National Medical Center; Jospeh Rosenthal, City of Hope National Medical Center; Susanta Hui, City of Hope National Medical Center; Amandeep Salhotra, City of Hope National Medical Center; Haris Ali, City of Hope National Medical Center; Ryotaro Nakamura, City of Hope National Medical Center; Anthony Stein, City of Hope National Medical Center; Monzr Al Malki, City of Hope National Medical Center; Jeffrey YC Wong, City of Hope National Medical Center; Savita Dandapani, City of Hope National Medical Center
• Journal Title: FRONTIERS IN ONCOLOGY
• Volume: Volume 12
• Publisher: FRONTIERS MEDIA SA | 2022-10-31, Pages 1017355-1017355
• Type of Work: Article | Final Publisher PDF
• Publisher DOI: http://doi.org/10.3389/fonc.2022.1017355
• Subjects: Health Sciences, Oncology; Physics, General; Biology, Biostatistics
• Keywords: Science & Technology; Life Sciences & Biomedicine; Oncology; TMLI; ALL; AML; leukemia; radiation; relapse; salvage; HCT role of radiation following TMLI; ACUTE MYELOID-LEUKEMIA; STEM-CELL TRANSPLANTATION; ACUTE MYELOGENOUS LEUKEMIA; BONE-MARROW; CHEMOTHERAPY; RADIATION; TRIAL

Abstract

Background: Total Marrow and Lymphoid Irradiation (TMLI) is a promising component of the preparative regimen for hematopoietic cell transplantation in patients with high-risk acute myeloid leukemia (AML) and acute lymphoid leukemia (ALL). Extramedullary (EM) relapse after TMLI is comparable to TBI and non-TBI conditioning regimens. This study evaluates outcomes of patients treated with radiotherapy (RT) with EM relapse previously treated with TMLI. Methods: A retrospective analysis of five prospective TMLI trials was performed. TMLI targeted bones and major lymphoid tissues using image-guided tomotherapy, with total dose ranging from 12 to 20 Gy. EM recurrences were treated at the discretion of the hematologist and radiation oncologist using RT ± chemotherapy. Descriptive statistics and survival analysis were then performed on this cohort. Results: In total, 254 patients with refractory or relapsed AML or ALL were treated with TMLI at our institution. Twenty-one patients were identified as receiving at least one subsequent course of radiation. A total of 67 relapse sites (median=2 sites/patient, range=1-16) were treated. Eleven relapsed patients were initially treated with curative intent. Following the initial course of subsequent RT, 1-year, 3-year and 5-year estimates of OS were 47.6%, 32.7% and 16.3%, respectively. OS was significantly better in patients treated with curative intent, with median OS of 50.7 months vs 1.6 months (p<0.001). 1-year, 3-year and 5-year estimates of PFS were 23.8%, 14.3% and 14.3%, respectively. PFS was significantly better in patients treated with curative intent, with median PFS of 6.6 months vs 1.3 months (p<0.001). Following RT, 86.6% of the sites had durable local control. Conclusions: RT is an effective modality to treat EM relapse in patients with acute leukemia who relapse after HCT achieving high levels of local control. In patients with limited relapse amenable to curative intent, radiation confers favorable long-term survival. Radiation as salvage treatment for EM relapse after HCT warrants further evaluation.