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Milgrom SA, Dandapani SV, Wong J, Kalapurakal J, Smith KS, Han C, Simiele E, Hua CH, Fitzgerald TJ, Kry S, Wong K, Symons H, Kovalchuk N, Hiniker SM. Incorporating intensity modulated total body irradiation into a Children's Oncology Group trial: Rationale, techniques, and safeguards. Pediatr Blood Cancer 2024:e31185. [PMID: 39118225 DOI: 10.1002/pbc.31185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Revised: 06/21/2024] [Accepted: 06/22/2024] [Indexed: 08/10/2024]
Abstract
Historically, total body irradiation (TBI) has been delivered using static, parallel opposed photon beams (2D-TBI). Recently, centers have increasingly used intensity-modulated radiation therapy (IMRT) techniques for TBI. Relative to 2D-TBI, IMRT can reduce doses to critical organs (i.e., lungs and kidneys) while delivering myeloablative doses to the rest of the body, so it may decrease the risk of toxicity while maintaining oncologic outcomes. Despite these potential benefits, delivering TBI using IMRT introduces new challenges in treatment planning and delivery. We describe the extensive experience with IMRT-based TBI at Stanford University and City of Hope Cancer Center. These groups, and others, have reported favorable clinical outcomes and have developed methods to optimize treatment planning and delivery. A critical next step is to evaluate the broader adoption of this approach. Therefore, IMRT-based TBI will be incorporated into a prospective, multi-institutional Children's Oncology Group study with careful procedures and safeguards in place.
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Affiliation(s)
- Sarah A Milgrom
- Department of Radiation Oncology, University of Colorado, Aurora, Colorado, USA
| | | | - Jeffrey Wong
- Department of Radiation Oncology, City of Hope, Duarte, California, USA
| | - John Kalapurakal
- Department of Radiation Oncology, Northwestern Medicine, Chicago, Illinois, USA
| | - Koren S Smith
- Department of Radiation Oncology, Imaging and Radiation Oncology Core-Rhode Island, UMass Chan Medical School, Lincoln, Rhode Island, USA
| | - Chunhui Han
- Department of Radiation Oncology, City of Hope, Duarte, California, USA
| | - Eric Simiele
- Department of Radiation Oncology, Stanford University, Palo Alto, California, USA
| | - Chia-Ho Hua
- Department of Radiation Oncology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Thomas J Fitzgerald
- Department of Radiation Oncology, Imaging and Radiation Oncology Core-Rhode Island, UMass Chan Medical School, Lincoln, Rhode Island, USA
| | - Stephen Kry
- Division of Radiation Oncology, MD Anderson Cancer Center, Houston, Texas, USA
| | - Kenneth Wong
- Department of Radiation Oncology, University of Southern California, Los Angeles, California, USA
| | - Heather Symons
- Department of Oncology, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins University, Baltimore, Maryland, USA
| | - Nataliya Kovalchuk
- Department of Radiation Oncology, Stanford University, Palo Alto, California, USA
| | - Susan M Hiniker
- Department of Radiation Oncology, Stanford University, Palo Alto, California, USA
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Seravalli E, Bosman ME, Han C, Losert C, Pazos M, Engström PE, Engellau J, Fulcheri CPL, Zucchetti C, Saldi S, Ferrer C, Ocanto A, Hiniker SM, Clark CH, Hussein M, Misson-Yates S, Kobyzeva DA, Loginova AA, Hoeben BAW. Technical recommendations for implementation of Volumetric Modulated Arc Therapy and Helical Tomotherapy Total Body Irradiation. Radiother Oncol 2024; 197:110366. [PMID: 38830537 DOI: 10.1016/j.radonc.2024.110366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 05/10/2024] [Accepted: 05/27/2024] [Indexed: 06/05/2024]
Abstract
As a component of myeloablative conditioning before allogeneic hematopoietic stem cell transplantation (HSCT), Total Body Irradiation (TBI) is employed in radiotherapy centers all over the world. In recent and coming years, many centers are changing their technical setup from a conventional TBI technique to multi-isocenter conformal arc therapy techniques such as Volumetric Modulated Arc Therapy (VMAT) or Helical Tomotherapy (HT). These techniques allow better homogeneity and control of the target prescription dose, and provide more freedom for individualized organ-at-risk sparing. The technical design of multi-isocenter/multi-plan conformal TBI is complex and should be developed carefully. A group of early adopters with conformal TBI experience using different treatment machines and treatment planning systems came together to develop technical recommendations and share experiences, in order to assist departments wishing to implement conformal TBI, and to provide ideas for standardization of practices.
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Affiliation(s)
- Enrica Seravalli
- Department of Radiation Oncology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Mirjam E Bosman
- Department of Radiation Oncology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Chunhui Han
- Department of Radiation Oncology, City of Hope National Medical Center, Duarte, CA, USA
| | - Christoph Losert
- Department of Radiation Oncology, University Hospital, LMU Munich, Germany
| | - Montserrat Pazos
- Department of Radiation Oncology, University Hospital, LMU Munich, Germany
| | - Per E Engström
- Department of Haematology, Oncology and Radiation Physics, Skåne University Hospital, Lund, Sweden
| | - Jacob Engellau
- Department of Radiation Oncology, Skåne University Hospital, Lund, Sweden
| | | | - Claudio Zucchetti
- Section of Medical Physics, Perugia General Hospital, Perugia, Italy
| | - Simonetta Saldi
- Section of Radiation Oncology, Perugia General Hospital, Perugia, Italy
| | - Carlos Ferrer
- Department of Medical Physics and Radiation Protection, La Paz University Hospital, Madrid, Spain
| | - Abrahams Ocanto
- Department of Radiation Oncology, San Francisco de Asís University Hospital, GenesisCare, Madrid, Spain
| | - Susan M Hiniker
- Department of Radiation Oncology, Stanford University, Stanford, CA, USA
| | - Catharine H Clark
- Radiotherapy Physics, National Radiotherapy Trials Quality Assurance Group (RTTQA), Mount Vernon Cancer Centre, Northwood, UK; Metrology for Medical Physics Centre, National Physical Laboratory, Teddington, UK; Radiotherapy Physics, University College London Hospitals NHS Foundation Trust, London, UK; Medical Physics and Bioengineering Department, University College London, London, UK
| | - Mohammad Hussein
- Metrology for Medical Physics Centre, National Physical Laboratory, Teddington, UK
| | - Sarah Misson-Yates
- Medical Physics Department, Guy's and St Thomas' Hospital, London, UK; UK School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK; National Physical Laboratory, Metrology for Medical Physics Centre, London, UK
| | - Daria A Kobyzeva
- Deptartment of Radiation Oncology, Dmitry Rogachev National Research Center of Pediatric Hematology, Oncology and Immunology, Moscow, Russia
| | - Anna A Loginova
- Deptartment of Radiation Oncology, Dmitry Rogachev National Research Center of Pediatric Hematology, Oncology and Immunology, Moscow, Russia
| | - Bianca A W Hoeben
- Department of Radiation Oncology, University Medical Center Utrecht, Utrecht, the Netherlands; Princess Máxima Center for Pediatric Oncology, Utrecht, the Netherlands.
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Melton MK, Stanley DN, Iqbal Z, Keene KS, Simiele E, McDonald A. Acute Toxicity of Total Body Irradiation Using Volumetric Arc Therapy With a Focus on the Effect of Lung Dose Rate. Adv Radiat Oncol 2024; 9:101430. [PMID: 38406392 PMCID: PMC10882112 DOI: 10.1016/j.adro.2023.101430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 11/27/2023] [Indexed: 02/27/2024] Open
Abstract
Purpose To report adverse effects of high dose total body irradiation (TBI) delivered using a volumetric arc therapy (VMAT) technique and to assess pulmonary toxicity at dose rates of 40 and 100 monitor units per minute (MU/min). Methods and Materials This retrospective study included patients >18 years old who received ≥8 Gy TBI using a VMAT technique. The TBI dose was prescribed to a planning target volume consisting of a 0.5 cm retraction of the body with the lungs subtracted. The objective function specified planning target volume coverage goals of D100% ≥ 90% and Dmax <130%. A lung dose control structure consisting of a 1 cm retraction of the lung volume was limited to Dmean <75%. Treatments were initially delivered with a dose rate of 40 MU/min for the thoracic isocenters and 100 MU/min for the other isocenters. Beginning in January 2021, a dose rate of 100 MU/min was used for all isocenters. All treatments were administered in 2 Gy fractions delivered twice daily. Acute toxicity was assessed for 30 days after TBI. Results A total of 29 patients were included in this analysis who received TBI between January 2019 and October 2021. Prescription dose ranged from 8 to 12 Gy. Mean lung dose was 7.9 Gy (SD, 1.4 Gy) for patients treated at 40 MU/min and for patients treated at 100 MU/min 7.1 Gy (SD, 1.3 Gy). Mucositis was the most common grade 3 toxicity and occurred in 10 (34%) patients. Only 1 instance of pneumonitis was observed and occurred in a patient who received a mean lung dose of 10.1 Gy delivered at 40 MU/min. Conclusions In this cohort of patients who received high dose TBI using a VMAT technique, the composite rate of acute toxicity was not unexpectedly high. We did not observe an increase in lung toxicity after increasing the dose rate of the thoracic isocenters from 40 MU/min to 100 MU/min.
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Affiliation(s)
- Michael Kole Melton
- Department of Radiation Oncology, The University of Alabama at Birmingham, Birmingham, Alabama
| | - Dennis N. Stanley
- Department of Radiation Oncology, The University of Alabama at Birmingham, Birmingham, Alabama
| | - Zohaib Iqbal
- Department of Radiation Oncology, The University of Texas Southwestern, Dallas, Texas
| | - Kimberly S. Keene
- Department of Radiation Oncology, The University of Alabama at Birmingham, Birmingham, Alabama
| | - Eric Simiele
- Department of Radiation Oncology, The University of Alabama at Birmingham, Birmingham, Alabama
| | - Andrew McDonald
- Department of Radiation Oncology, The University of Alabama at Birmingham, Birmingham, Alabama
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Shyr D, Davis KL, Bertaina A. Stem cell transplantation for ALL: you've always got a donor, why not always use it? HEMATOLOGY. AMERICAN SOCIETY OF HEMATOLOGY. EDUCATION PROGRAM 2023; 2023:84-90. [PMID: 38066901 PMCID: PMC10726989 DOI: 10.1182/hematology.2023000423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
Hematopoietic stem cell transplantation (HSCT) represents a consolidated therapeutic strategy for high-risk pediatric acute lymphoblastic leukemia (ALL), offering the potential for curative treatment. This manuscript delves into the debate around the more universal application of HSCT for pediatric ALL in the modern era, considering the ubiquitous availability of suitable donors. In fact, despite significant advancements in chemotherapy, targeted therapy, and immunotherapy, a subset of pediatric patients with ALL with high-risk features or relapse continue to encounter poor prognostic outcomes. For this subgroup of patients, HSCT often remains the only potentially curative measure, leveraging the graft-versus- leukemia effect for long-term disease control. Nevertheless, the procedure's complexity and associated risks have traditionally curtailed its widespread use. However, the scenario is shifting with improvements in HLA matching, availability of alternative donor sources, less toxic conditioning regimens, and improved supportive care protocols. Concurrently, emerging therapies like CD19+ CAR T cells present new considerations for definitive therapy selection in relapsed/ refractory ALL. This article reviews critical current evidence and debates the potential of HSCT as a more universal treatment for ALL, reevaluating traditional treatment stratification in light of the constant availability of stem cell donors.
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Affiliation(s)
- David Shyr
- Division of Hematology, Oncology, Stem Cell Transplantation and Regenerative Medicine, Department of Pediatrics, Stanford University School of Medicine, Palo Alto, CA
- Center for Definitive and Curative Medicine, Department of Pediatrics, Stanford University School of Medicine, Palo Alto, CA
| | - Kara L Davis
- Division of Hematology, Oncology, Stem Cell Transplantation and Regenerative Medicine, Department of Pediatrics, Stanford University School of Medicine, Palo Alto, CA
- Center for Cancer Cellular Therapy, Stanford University School of Medicine, Palo Alto, CA
| | - Alice Bertaina
- Division of Hematology, Oncology, Stem Cell Transplantation and Regenerative Medicine, Department of Pediatrics, Stanford University School of Medicine, Palo Alto, CA
- Center for Definitive and Curative Medicine, Department of Pediatrics, Stanford University School of Medicine, Palo Alto, CA
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Ngo N, Blomain ES, Simiele E, Romero I, Hoppe RT, Hiniker SM, Kovalchuk N. Improved organ sparing using auto-planned Stanford volumetric modulated arc therapy for total body irradiation technique. Pediatr Blood Cancer 2023; 70:e30589. [PMID: 37486149 DOI: 10.1002/pbc.30589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 07/07/2023] [Accepted: 07/08/2023] [Indexed: 07/25/2023]
Abstract
PURPOSE/OBJECTIVES To evaluate dosimetric differences between auto-planned volumetric modulated arc therapy (VMAT) total body irradiation (TBI) technique and two-dimensional radiotherapy using anterior-posterial/posterio-anterial beams (2D AP/PA) TBI technique. METHODS Ten pediatric patients treated with VMAT-TBI on Varian c-arm linac were included in this study. VMAT-TBI plans were generated using our in-house developed and publicly shared auto-planning scripts. For each VMAT-TBI plan, a 2D AP/PA plan was created replicating the institution's clinical setup with the patient positioned at extended source to skin distance (SSD) with a compensator to account for differences in patient thickness, 50% transmission daily lung blocks, and electron chest wall boosts prescribed to 50% of the photon prescription. Clinically relevant metrics were analyzed and compared between the VMAT and 2D plans. RESULTS All VMAT-TBI plans achieved planned target volume (PTV) D90% ≥ 100% of prescription. VMAT-TBI PTV D90% significantly increased (7.1% ± 2.9%, p < .001) compared to the 2D technique, whereas no differences were observed in global Dmax (p < .2) and PTV V110% (p < .4). Compared to the 2D plans, significant decreases in the Dmean to the lungs (-25.6% ± 11.5%, p < .001) and lungs-1 cm (-34.1% ± 10.1%, p < .001) were observed with the VMAT plans. The VMAT technique also enabled decrease of dose to other organs: kidneys Dmean (-32.5% ± 5.0%, p < .001) and lenses Dmax (-5.3% ± 8.1%, p = .03); and in addition, for 2 Gy prescription: testes/ovaries Dmean (-41.5% ± 11.5%, p < .001), brain Dmean (-22.6% ± 5.4%, p = .002), and thyroid Dmean (-18.2% ± 16.0%, p = .03). CONCLUSIONS Superior lung sparing with improved target coverage and similar global Dmax were observed with the VMAT plans as compared to 2D plans. In addition, VMAT-TBI plans provided greater dose reductions in gonads, kidneys, brain, thyroid, and lenses.
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Affiliation(s)
- Nicholas Ngo
- Radiation Oncology Department, Stanford University Cancer Center, Palo Alto, California, USA
| | - Erik S Blomain
- Radiation Oncology Department, Stanford University Cancer Center, Palo Alto, California, USA
| | - Eric Simiele
- Radiation Oncology Department, Stanford University Cancer Center, Palo Alto, California, USA
| | - Ignacio Romero
- Radiation Oncology Department, Stanford University Cancer Center, Palo Alto, California, USA
| | - Richard T Hoppe
- Radiation Oncology Department, Stanford University Cancer Center, Palo Alto, California, USA
| | - Susan M Hiniker
- Radiation Oncology Department, Stanford University Cancer Center, Palo Alto, California, USA
| | - Nataliya Kovalchuk
- Radiation Oncology Department, Stanford University Cancer Center, Palo Alto, California, USA
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Hao C, Ladbury C, Wong J, Dandapani S. Modern Radiation for Hematologic Stem Cell Transplantation: Total Marrow and Lymphoid Irradiation or Intensity-Modulated Radiation Therapy Total Body Irradiation. Surg Oncol Clin N Am 2023; 32:475-495. [PMID: 37182988 DOI: 10.1016/j.soc.2023.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The development of large-field intensity-modulated radiation therapy (IMRT) has enabled the implementation of total marrow irradiation (TMI), total marrow and lymphoid irradiation (TMLI), and IMRT total body irradiation (TBI). IMRT TBI limits doses to organs at risk, primarily the lungs and in some cases the kidneys and lenses, which may mitigate complications. TMI/TMLI allows for dose escalation above TBI radiation therapy doses to malignant sites while still sparing organs at risk. Although still sparingly used, these techniques have established feasibility and demonstrated promise in reducing the adverse effects of TBI while maintaining and potentially improving survival outcomes.
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Affiliation(s)
- Claire Hao
- Department of Radiation Oncology, City of Hope, 1500 East Duarte Road, Duarte, CA 91010, USA
| | - Colton Ladbury
- Department of Radiation Oncology, City of Hope, 1500 East Duarte Road, Duarte, CA 91010, USA
| | - Jeffrey Wong
- Department of Radiation Oncology, City of Hope, 1500 East Duarte Road, Duarte, CA 91010, USA
| | - Savita Dandapani
- Department of Radiation Oncology, City of Hope, 1500 East Duarte Road, Duarte, CA 91010, USA.
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Ladbury C, Hao C, Yang D, Hui S, Han C, Liu A, Salhotra A, Nakamura R, Rosenthal J, Stein A, Wong J, Dandapani S. Long-term follow up of patients with hematological malignancies treated with total body irradiation using intensity modulated radiation therapy. Front Oncol 2022; 12:1044539. [PMID: 36531001 PMCID: PMC9755353 DOI: 10.3389/fonc.2022.1044539] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 11/18/2022] [Indexed: 09/28/2023] Open
Abstract
BACKGROUND With the advent of modern radiation treatment technologies such as intensity modulated radiation therapy (IMRT), there has been increasing interest in its use for total body irradiation (TBI) conditioning regimens for hematopoietic cell transplantation (HCT) to achieve lower doses to critical organs such as the lungs and kidneys. Although this has been reported on in early studies, long-term safety and efficacy data is limited. METHODS We performed a single institution matched-pair retrospective analysis of patients treated with IMRT TBI and standard TBI between 2010 and 2020 to provide data on long-term outcomes. Patients with hematologic malignancies, who could not tolerate standing for traditional TBI or who received prior radiation received IMRT TBI. Patients were matched based on age, diagnosis, disease status, and year of transplant, and were matched 2:1 to the standard TBI and IMRT TBI cohorts. Patient and treatment characteristics, toxicity, graft-versus-host disease (GVHD), dosimetry, and outcomes were evaluated for each cohort. RESULTS A total of 13 patients met inclusion criteria for the IMRT cohort, leading to 26 patients in the standard TBI cohort. There was no significant difference in relevant clinical factors between the cohorts. Reasons for using IMRT over conventional TBI included being unable to stand (n=5), prior radiation (n=5), and pediatric patient requiring anesthesia (n=3). Among living patients, median follow-up for all patients was 5.1 years in the IMRT TBI cohort and 5.5 years in the standard TBI cohort. The 5-yr estimate of OS was 68% in the IMRT TBI cohort and 60% in the standard TBI cohort (p=0.706). The 5-yr estimate of RFS was 54% in the IMRT TBI cohort and 60% in the standard TBI cohort (p=0.529). There was no clinically significant pneumonitis, nephritis, hypothyroidism, or cataracts reported in the IMRT TBI cohort. 41.7% of patients in the IMRT TBI cohort and 79.2% of patients in the standard TBI cohort experienced Grade II-IV acute GVHD (p=0.023). CONCLUSIONS IMRT TBI appears to lead to favorable long-term outcome and dosimetry, and therefore potentially improved long-term toxicity profile compared to conventional TBI. IMRT TBI warrants further investigation as part of larger prospective trials.
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Affiliation(s)
- Colton Ladbury
- Department of Radiation Oncology, City of Hope National Medical Center, Duarte, CA, United States
| | - Claire Hao
- Department of Radiation Oncology, City of Hope National Medical Center, Duarte, CA, United States
| | - Dongyun Yang
- Division of Biostatistics, City of Hope National Medical Center, Duarte, CA, United States
| | - Susanta Hui
- Department of Radiation Oncology, City of Hope National Medical Center, Duarte, CA, United States
| | - Chunhui Han
- Department of Radiation Oncology, City of Hope National Medical Center, Duarte, CA, United States
| | - An Liu
- Department of Radiation Oncology, City of Hope National Medical Center, Duarte, CA, United States
| | - Amandeep Salhotra
- Department of Hematology and Hematopoietic Cell Transplantation, City of Hope National Medical Center, Duarte, CA, United States
| | - Ryotaro Nakamura
- Department of Hematology and Hematopoietic Cell Transplantation, City of Hope National Medical Center, Duarte, CA, United States
| | - Joseph Rosenthal
- Department of Hematology and Hematopoietic Cell Transplantation, City of Hope National Medical Center, Duarte, CA, United States
| | - Anthony Stein
- Department of Hematology and Hematopoietic Cell Transplantation, City of Hope National Medical Center, Duarte, CA, United States
| | - Jeffrey Wong
- Department of Radiation Oncology, City of Hope National Medical Center, Duarte, CA, United States
| | - Savita Dandapani
- Department of Radiation Oncology, City of Hope National Medical Center, Duarte, CA, United States
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Full Body Surface Coverage with Water-Equivalent Bolus as Novel Technique for Total Body Irradiation before Hematopoietic Stem Cell Transplantation in Pediatric Acute Lymphoid Leukemia. CHILDREN 2022; 9:children9111740. [DOI: 10.3390/children9111740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 11/07/2022] [Accepted: 11/10/2022] [Indexed: 11/16/2022]
Abstract
Background: Total body irradiation (TBI) 2 × 2 Gy for 3 consecutive days followed by chemotherapy for conditioning pediatric patients with acute lymphoid leukemia (ALL) before bone marrow transplantation is superior to chemo-conditioning alone. The globally used anterior-posterior/posterior-anterior (AP/PA) technique is the most referable method, but volumetric modulated arc therapy (VMAT) with modern linear accelerators is more precise in terms of ensuring better dose distribution, especially for skin, and higher protection of organs at risk, resulting in less side effects. Method: For TBI, a modern VMAT technique was used. Whole-body immobilization in the supine position was performed using a vacuum mattress with a full body coverage, with a water-equivalent bolus of 1 cm thickness. The design goal was to achieve dose inhomogeneity of less than ±10%. Results: From 2020 to 2022, we performed TBI for five pediatric patients with ALL, with full body bolus and VMAT, who later received hematopoietic stem cell transplantation. No acute complications related to TBI were observed during the treatment period with a median follow-up of 1.27 (0.43–2.11) years. Conclusion: Using full body water-equivalent bolus with VMAT for TBI provides a safe method for children with a better organ sparing in the short term follow-up.
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