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Paganetti H. Proton Relative Biological Effectiveness - Uncertainties and Opportunities. Int J Part Ther 2018; 5:2-14. [PMID: 30370315 DOI: 10.14338/ijpt-18-00011.1] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Proton therapy treatments are prescribed using a biological effectiveness relative to photon therapy of 1.1, that is, proton beams are considered to be 10% more biologically effective. Debate is ongoing as to whether this practice needs to be revised. This short review summarizes current knowledge on relative biological effectiveness variations and uncertainties in vitro and in vivo. Clinical relevance is discussed and strategies toward biologically guided treatment planning are presented.
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Affiliation(s)
- Harald Paganetti
- Department of Radiation Oncology, Massachusetts General Hospital, and Harvard Medical School, Boston, MA, USA
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Guan F, Geng C, Ma D, Bronk L, Kerr M, Li Y, Gates D, Kroger B, Sahoo N, Titt U, Grosshans D, Mohan R. RBE Model-Based Biological Dose Optimization for Proton Radiobiology Studies. Int J Part Ther 2018; 5:160-171. [PMID: 30338268 DOI: 10.14338/ijpt-18-00007.1] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Purpose The purpose of the current study was (1) to develop a straightforward and rapid method to incorporate a dose-averaged linear energy transfer (LET d )-based biological effect model into a dose optimization algorithm for scanned protons; and (2) to apply a novel beam delivery strategy with increased LET d within the target, thereby enhancing the biological effect predicted using the selected relative biological effectiveness (RBE) model. Materials and Methods We first generated pristine dose Bragg curves in water and their corresponding LET d distributions for 94 groups of proton beams, using experimentally validated Geant4 Monte Carlo simulations. Next, we developed 1-dimensional dose optimization algorithms by using the Python programming language. To calculate the RBE of protons for biological dose optimization, we invoked the McNamara RBE model and applied the radiobiological parameters of the lung cancer H460 cell line with 137Cs reference photons. Results High-accuracy optimization results were obtained. The relative difference between the delivered dose and the prescribed dose was approximately within ±1.0% in the target. In addition, we obtained the RBE enhancement within the target by applying the LET-painting technique. For example, considering a simple case in which 2 opposed downslope dose fields were superimposed to form a uniform dose in the 5- to 10-cm target region, the center RBE was 1.23 ± 0.01, which was greater than the center RBE of 1.16 ± 0.01 found when using the traditional method of delivering 2 opposed flat dose fields. Conclusion We have successfully developed an easy-to-implement method to perform the biological dose optimization procedure by invoking the McNamara RBE model in the iteration process using the Python programming language. According to the RBE model predictions, we conclude that the increased target LET d enhances the RBE. The accuracy of the RBE model predictions needs to be validated in radiobiological experiments.
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Affiliation(s)
- Fada Guan
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Changran Geng
- Department of Nuclear Science and Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, China
| | - Duo Ma
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Lawrence Bronk
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Matthew Kerr
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Yuting Li
- Department of Radiation Oncology, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Drake Gates
- Orbital Debris Program Office, NASA Johnson Space Center, Houston, TX, USA
| | - Benjamin Kroger
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Narayan Sahoo
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Uwe Titt
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - David Grosshans
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Radhe Mohan
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
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Deycmar S, Pruschy M. Combined Treatment Modalities for High-Energy Proton Irradiation: Exploiting Specific DNA Repair Dependencies. Int J Part Ther 2018; 5:133-139. [DOI: 10.14338/ijpt-18-00020.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 07/05/2018] [Indexed: 11/21/2022] Open
Affiliation(s)
- Simon Deycmar
- Department of Radiation Oncology, Laboratory for Applied Radiobiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Martin Pruschy
- Department of Radiation Oncology, Laboratory for Applied Radiobiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
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Underwood TS, McMahon SJ. Proton relative biological effectiveness (RBE): a multiscale problem. Br J Radiol 2018; 92:20180004. [PMID: 29975153 DOI: 10.1259/bjr.20180004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Proton radiotherapy is undergoing rapid expansion both within the UK and internationally, but significant challenges still need to be overcome if maximum benefit is to be realised from this technique. One major limitation is the persistent uncertainty in proton relative biological effectiveness (RBE). While RBE values are needed to link proton radiotherapy to our existing experience with photon radiotherapy, RBE remains poorly understood and is typically incorporated as a constant dose scaling factor of 1.1 in clinical plans. This is in contrast to extensive experimental evidence indicating that RBE is a function of dose, tissue type, and proton linear energy transfer, among other parameters. In this article, we discuss the challenges associated with obtaining clinically relevant values for proton RBE through commonly-used assays, and highlight the wide range of other experimental end points which can inform our understanding of RBE. We propose that accurate and robust optimization of proton radiotherapy ultimately requires a multiscale understanding of RBE, integrating subcellular, cellular, and patient-level processes.
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Affiliation(s)
- Tracy Sa Underwood
- Department of Medical Physics and Biomedical Engineering, University College London, London, UK
| | - Stephen J McMahon
- Centre for Cancer Research and Cell Biology, School of Medicine, Dentistry and Biomedical Science, Queen's University Belfast, Belfast, UK
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Dosanjh M, Jones B, Pawelke J, Pruschy M, Sørensen BS. Overview of research and therapy facilities for radiobiological experimental work in particle therapy. Report from the European Particle Therapy Network radiobiology group. Radiother Oncol 2018; 128:14-18. [DOI: 10.1016/j.radonc.2018.03.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 03/13/2018] [Accepted: 03/13/2018] [Indexed: 11/30/2022]
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Relative Biological Effectiveness Uncertainties and Implications for Beam Arrangements and Dose Constraints in Proton Therapy. Semin Radiat Oncol 2018; 28:256-263. [DOI: 10.1016/j.semradonc.2018.02.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Toward A variable RBE for proton beam therapy. Radiother Oncol 2018; 128:68-75. [PMID: 29910006 DOI: 10.1016/j.radonc.2018.05.019] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 05/09/2018] [Accepted: 05/17/2018] [Indexed: 12/19/2022]
Abstract
In the clinic, proton beam therapy (PBT) is based on the use of a generic relative biological effectiveness (RBE) of 1.1 compared to photons in human cancers and normal tissues. However, the experimental basis for this RBE lacks any significant number of representative tumor models and clinically relevant endpoints for dose-limiting organs at risk. It is now increasingly appreciated that much of the variations of treatment responses in cancers are due to inter-tumoral genomic heterogeneity. Indeed, recently it has been shown that defects in certain DNA repair pathways, which are found in subsets of many cancers, are associated with a RBE increase in vitro. However, there currently exist little in vivo or clinical data that confirm the existence of similarly increased RBE values in human cancers. Furthermore, evidence for variable RBE values for normal tissue toxicity has been sparse and conflicting to date. If we could predict variable RBE values in patients, we would be able to optimally use and personalize PBT. For example, predictive tumor biomarkers may facilitate selection of patients with proton-sensitive cancers previously ineligible for PBT. Dose de-escalation may be possible to reduce normal tissue toxicity, especially in pediatric patients. Knowledge of increased tumor RBE may allow us to develop biologically optimized therapies to enhance local control while RBE biomarkers for normal tissues could lead to a better understanding and prevention of unusual PBT-associated toxicity. Here, we will review experimental data on the repair of proton damage to DNA that impact both RBE values and biophysical modeling to predict RBE variations. Experimental approaches for studying proton sensitivity in vitro and in vivo will be reviewed as well and recent clinical findings discussed. Ultimately, therapeutically exploiting the understudied biological advantages of protons and developing approaches to limit treatment toxicity should fundamentally impact the clinical use of PBT.
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Lühr A, von Neubeck C, Pawelke J, Seidlitz A, Peitzsch C, Bentzen SM, Bortfeld T, Debus J, Deutsch E, Langendijk JA, Loeffler JS, Mohan R, Scholz M, Sørensen BS, Weber DC, Baumann M, Krause M. "Radiobiology of Proton Therapy": Results of an international expert workshop. Radiother Oncol 2018; 128:56-67. [PMID: 29861141 DOI: 10.1016/j.radonc.2018.05.018] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 05/17/2018] [Accepted: 05/17/2018] [Indexed: 12/25/2022]
Abstract
The physical properties of proton beams offer the potential to reduce toxicity in tumor-adjacent normal tissues. Toward this end, the number of proton radiotherapy facilities has steeply increased over the last 10-15 years to currently around 70 operational centers worldwide. However, taking full advantage of the opportunities offered by proton radiation for clinical radiotherapy requires a better understanding of the radiobiological effects of protons alone or combined with drugs or immunotherapy on normal tissues and tumors. This report summarizes the main results of the international expert workshop "Radiobiology of Proton Therapy" that was held in November 2016 in Dresden. It addresses the major topics (1) relative biological effectiveness (RBE) in proton beam therapy, (2) interaction of proton radiobiology with radiation physics in current treatment planning, (3) biological effects in proton therapy combined with systemic treatments, and (4) testing biological effects of protons in clinical trials. Finally, important research avenues for improvement of proton radiotherapy based on radiobiological knowledge are identified. The clinical distribution of radiobiological effectiveness of protons alone or in combination with systemic chemo- or immunotherapies as well as patient stratification based on biomarker expressions are key to reach the full potential of proton beam therapy. Dedicated preclinical experiments, innovative clinical trial designs, and large high-quality data repositories will be most important to achieve this goal.
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Affiliation(s)
- Armin Lühr
- Helmholtz-Zentrum Dresden - Rossendorf, Institute of Radiooncology - OncoRay, Germany; OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden - Rossendorf, Germany; German Cancer Consortium (DKTK), Partner Site Dresden and German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Cläre von Neubeck
- OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden - Rossendorf, Germany; German Cancer Consortium (DKTK), Partner Site Dresden and German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Jörg Pawelke
- Helmholtz-Zentrum Dresden - Rossendorf, Institute of Radiooncology - OncoRay, Germany; OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden - Rossendorf, Germany
| | - Annekatrin Seidlitz
- OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden - Rossendorf, Germany; German Cancer Consortium (DKTK), Partner Site Dresden and German Cancer Research Center (DKFZ), Heidelberg, Germany; Department of Radiotherapy and Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Germany
| | - Claudia Peitzsch
- OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden - Rossendorf, Germany; German Cancer Consortium (DKTK), Partner Site Dresden and German Cancer Research Center (DKFZ), Heidelberg, Germany; National Center for Tumor Diseases (NCT), Partner Site Dresden, Germany: German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany, and; Helmholtz Association/Helmholtz-Zentrum Dresden - Rossendorf (HZDR), Germany
| | - Søren M Bentzen
- Division of Biostatistics and Bioinformatics, Department of Epidemiology and Public Health and the Maryland Proton Therapy Center, Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, USA
| | - Thomas Bortfeld
- Physics Division, Department of Radiation Oncology, Massachusetts General Hospital, Boston, USA
| | - Jürgen Debus
- German Cancer Research Center (DKFZ), Heidelberg, Germany; Department of Radiation Oncology, University Heidelberg German Consortium for Translational Oncology (DKTK), Germany; National Center for Tumor Diseases (NCT), Heidelberg, Germany
| | - Eric Deutsch
- Department of Radiation Oncology Gustave Roussy Cancer Campus, INSERM, 1030 Villejuif, France; Université Paris-Sud, Faculté de Medecine du Kremlin Bicetre Paris Sud, Le Kremlin-Bicêtre, France
| | - Johannes A Langendijk
- Department of Radiation Oncology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Jay S Loeffler
- Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, USA; Department of Neurosurgery, Massachusetts General Hospital and Harvard Medical School, USA
| | - Radhe Mohan
- Department of Radiation Physics, UT MD Anderson Cancer Center, Houston, USA
| | - Michael Scholz
- GSI Helmholtz Center for Heavy Ion Research, Department of Biophysics, Darmstadt, Germany
| | - Brita S Sørensen
- Dept. Experimental Clinical Oncology, Aarhus University Hospital, Denmark
| | - Damien C Weber
- Center for Proton Therapy, Paul Scherrer Institute, ETH Domain, Villigen, Switzerland
| | - Michael Baumann
- Helmholtz-Zentrum Dresden - Rossendorf, Institute of Radiooncology - OncoRay, Germany; OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden - Rossendorf, Germany; German Cancer Consortium (DKTK), Partner Site Dresden and German Cancer Research Center (DKFZ), Heidelberg, Germany; Department of Radiotherapy and Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Germany; National Center for Tumor Diseases (NCT), Partner Site Dresden, Germany: German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany, and; Helmholtz Association/Helmholtz-Zentrum Dresden - Rossendorf (HZDR), Germany; German Cancer Research Center (DKFZ), Heidelberg, Germany.
| | - Mechthild Krause
- Helmholtz-Zentrum Dresden - Rossendorf, Institute of Radiooncology - OncoRay, Germany; OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden - Rossendorf, Germany; German Cancer Consortium (DKTK), Partner Site Dresden and German Cancer Research Center (DKFZ), Heidelberg, Germany; Department of Radiotherapy and Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Germany; National Center for Tumor Diseases (NCT), Partner Site Dresden, Germany: German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany, and; Helmholtz Association/Helmholtz-Zentrum Dresden - Rossendorf (HZDR), Germany
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PARP-1 inhibition with or without ionizing radiation confers reactive oxygen species-mediated cytotoxicity preferentially to cancer cells with mutant TP53. Oncogene 2018; 37:2793-2805. [PMID: 29511347 PMCID: PMC5970015 DOI: 10.1038/s41388-018-0130-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 10/13/2017] [Accepted: 11/24/2017] [Indexed: 01/05/2023]
Abstract
Biomarkers and mechanisms of poly (ADP-ribose) polymerase (PARP) inhibitor-mediated cytotoxicity in tumor cells lacking a BRCA-mutant or BRCA-like phenotype are poorly defined. We sought to explore the utility of PARP-1 inhibitor (PARPi) treatment with/without ionizing radiation in muscle-invasive bladder cancer (MIBC), which has poor therapeutic outcomes. We assessed the DNA damaging and cytotoxic effects of the PARPi olaparib in nine bladder cancer cell lines. Olaparib radiosensitized all cell lines with dose enhancement factors from 1.22 to 2.27. Radiosensitization was correlated with the induction of potentially lethal DNA double-strand breaks (DSB) but not with RAD51 foci formation. The ability of olaparib to radiosensitize MIBC cells was linked to the extent of cell kill achieved with drug alone. Unexpectedly, increased levels of reactive oxygen species (ROS) resulting from PARPi treatment were the cause of DSB throughout the cell cycle in-vitro and in-vivo. ROS originated from mitochondria and were required for the radiosensitizing effects of olaparib. Consistent with the role of TP53 in ROS regulation, loss of p53 function enhanced radiosensitization by olaparib in non-isogenic and isogenic cell line models and was associated with increased PARP-1 expression in bladder cancer cell lines and tumors. Impairment of ATM in addition to p53 loss resulted in an even more pronounced radiosensitization. In conclusion, ROS suppression by PARP-1 in MIBC is a potential therapeutic target either for PARPi combined with radiation or drug alone treatment. The TP53 and ATM genes, commonly mutated in MIBC and other cancers, are candidate biomarkers of PARPi-mediated radiosensitization.
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Jones B, McMahon SJ, Prise KM. The Radiobiology of Proton Therapy: Challenges and Opportunities Around Relative Biological Effectiveness. Clin Oncol (R Coll Radiol) 2018; 30:285-292. [PMID: 29454504 DOI: 10.1016/j.clon.2018.01.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 01/16/2018] [Indexed: 01/31/2023]
Abstract
With the current UK expansion of proton therapy there is a great opportunity for clinical oncologists to develop a translational interest in the associated scientific base and clinical results. In particular, the underpinning controversy regarding the conversion of photon dose to proton dose by the relative biological effectiveness (RBE) must be understood, including its important implications. At the present time, the proton prescribed dose includes an RBE of 1.1 regardless of tissue, tumour and dose fractionation. A body of data has emerged against this pragmatic approach, including a critique of the existing evidence base, due to choice of dose, use of only acute-reacting in vivo assays, analysis methods and the reference radiations used to determine the RBE. Modelling systems, based on the best available scientific evidence, and which include the clinically useful biological effective dose (BED) concept, have also been developed to estimate proton RBEs for different dose and linear energy transfer (LET) values. The latter reflect ionisation density, which progressively increases along each proton track. Late-reacting tissues, such as the brain, where α/β = 2 Gy, show a higher RBE than 1.1 at a low dose per fraction (1.2-1.8 Gy) at LET values used to cover conventional target volumes and can be much higher. RBE changes with tissue depth seem to vary depending on the method of beam delivery used. To reduce unexpected toxicity, which does occasionally follow proton therapy, a more rational approach to RBE allocation, using a variable RBE that depends on dose per fraction and the tissue and tumour radiobiological characteristics such as α/β, is proposed.
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Affiliation(s)
- B Jones
- Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Oxford, UK.
| | - S J McMahon
- Centre for Cancer Research & Cell Biology, Queen's University Belfast, Belfast, UK
| | - K M Prise
- Centre for Cancer Research & Cell Biology, Queen's University Belfast, Belfast, UK
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Proceedings of the National Cancer Institute Workshop on Charged Particle Radiobiology. Int J Radiat Oncol Biol Phys 2017; 100:816-831. [PMID: 29485053 DOI: 10.1016/j.ijrobp.2017.12.260] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 12/05/2017] [Accepted: 12/11/2017] [Indexed: 12/21/2022]
Abstract
In April 2016, the National Cancer Institute hosted a multidisciplinary workshop to discuss the current knowledge of the radiobiological aspects of charged particles used in cancer therapy to identify gaps in that knowledge that might hinder the effective clinical use of charged particles and to propose research that could help fill those gaps. The workshop was organized into 10 topics ranging from biophysical models to clinical trials and included treatment optimization, relative biological effectiveness of tumors and normal tissues, hypofractionation with particles, combination with immunotherapy, "omics," hypoxia, and particle-induced second malignancies. Given that the most commonly used charged particle in the clinic currently is protons, much of the discussion revolved around evaluating the state of knowledge and current practice of using a relative biological effectiveness of 1.1 for protons. Discussion also included the potential advantages of heavier ions, notably carbon ions, because of their increased biological effectiveness, especially for tumors frequently considered to be radiation resistant, increased effectiveness in hypoxic cells, and potential for differentially altering immune responses. The participants identified a large number of research areas in which information is needed to inform the most effective use of charged particles in the future in clinical radiation therapy. This unique form of radiation therapy holds great promise for improving cancer treatment.
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Valproic Acid Sensitizes Hepatocellular Carcinoma Cells to Proton Therapy by Suppressing NRF2 Activation. Sci Rep 2017; 7:14986. [PMID: 29118323 PMCID: PMC5678087 DOI: 10.1038/s41598-017-15165-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 10/23/2017] [Indexed: 01/08/2023] Open
Abstract
Although efficacy of combined histone deacetylase (HDAC) inhibitors and conventional photon radiotherapy is being tested in clinical trials, their combined effect with proton beam radiotherapy has yet to be determined. Here, we compared combined effect of valproic acid (VPA), a class I and II HDAC inhibitor and antiepileptic drug with proton and photon irradiation in hepatocellular carcinoma (HCC) cells in vitro and in vivo. We found that VPA sensitized more Hep3B cells to proton than to photon irradiation. VPA prolonged proton-induced DNA damage and augmented proton-induced apoptosis. In addition, VPA further increased proton-induced production of intracellular reactive oxygen species and suppressed expression of nuclear factor erythroid-2-related factor 2 (NRF2), a key transcription factor regulating antioxidant response. Downregulation of NRF2 by siRNA transfection increased proton-induced apoptotic cell death, supporting NRF2 as a target of VPA in radiosensitization. In Hep3B tumor xenograft models, VPA significantly enhanced proton-induced tumor growth delay with increased apoptosis and decreased NRF2 expression in vivo. Collectively, our study highlights a proton radiosensitizing effect of VPA in HCC cells. As NRF2 is an emerging prognostic marker contributing to radioresistance in HCC, targeting NRF2 pathway may impact clinical outcome of proton beam radiotherapy.
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Paganetti H. Relating the proton relative biological effectiveness to tumor control and normal tissue complication probabilities assuming interpatient variability in α/β. Acta Oncol 2017; 56:1379-1386. [PMID: 28918679 DOI: 10.1080/0284186x.2017.1371325] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
BACKGROUND Proton therapy uses a constant relative biological effectiveness (RBE) of 1.1. The use of variable RBE values has been suggested but is currently not feasible due to uncertainties. The impact of variable RBE has solely been studied using dosimetric indices. This work elucidates the impact of RBE variations on tumor control and normal tissue complication probabilities (TCP/NTCP). METHODS Models to estimate TCP and NTCP were used in combination with an empirical proton RBE model. Variations in outcome as a function of linear-quadratic model parameters for cellular radiosensitivity were determined for TCP in prostate and ependymoma. In addition, NTCP analysis was done for brainstem necrosis. RESULTS Considering a variable proton RBE as a dose-modifying factor for prescription doses and dose constraints is misleading, as TCP/NTCP do not simply scale with RBE. The dependency of RBE on α/β cannot be interpreted independent of TCP/NTCP because variations in radiosensitivity affect both photon and proton treatments. Assuming interpatient variability in radiosensitivity results in lower TCP for patients with low α/β. In proton therapy, the magnitude of TCP variations is reduced due to an RBE increase as α/β decreases. The TCP in proton therapy is less affected by interpatient variability in α/β. On the other hand, patients with a lower α/β would have a lower complication probability, which is counteracted by an increase in RBE as α/β decreases. Toxicities in proton therapy would be more affected by α/β variations compared to photon therapy. CONCLUSIONS Assessment of variable RBE in proton therapy should be based on TCP and NTCP. Potential interpatient variability in radiosensitivity causes a smaller variance in TCP but a larger variance in NTCP for proton patients. The relative TCP as a function of α/β was found to be higher than the RBE, whereas the relative NTCP was lower than a calculated RBE.
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Affiliation(s)
- Harald Paganetti
- Department of Radiation Oncology, Massachusetts General Hospital & Harvard Medical School, Boston, MA, USA
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Grosshans DR, Mohan R, Gondi V, Shih HA, Mahajan A, Brown PD. The role of image-guided intensity modulated proton therapy in glioma. Neuro Oncol 2017; 19:ii30-ii37. [PMID: 28380636 DOI: 10.1093/neuonc/nox002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Gliomas represent a broad spectrum of disease with life-expectancy outcomes ranging from months to decades. As our understanding of the molecular profiles of gliomas expands rapidly, practitioners are now better able to identify patients with favorable versus nonfavorable prognoses. Radiation therapy plays a key role in glioma treatment, improving disease control and oftentimes survival. However, for survivors, either long-term or short-term, radiation-induced cognitive impairments may negatively impact their quality of life. For patients with both favorable and unfavorable prognoses, intensity modulated proton therapy (IMPT) may offer significant, yet unproven benefits. IMPT is the newest and most advanced proton delivery technique, one with substantial benefits compared with historical proton techniques. IMPT allows practitioners to maximize the physical benefits of protons, increasing normal tissue sparing and reducing the potential for adverse effects. For more aggressive tumors, the dose conformality and normal tissue sparing afforded by IMPT may also allow for dose escalation to target volumes. However, in order to truly maximize the clinical potential of IMPT, the field of radiation oncology must not only implement the most advanced technologies, but also understand and capitalize on the unique biologic aspects of proton therapy.
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Affiliation(s)
- David R Grosshans
- Departments of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Radhe Mohan
- Department of Surgical Oncology, New Hope Medical Centre, Kilpauk, Chennai, Tamil Nadu, India
| | - Vinai Gondi
- Northwestern Medicine Chicago Proton Center, Warrenville, Illinois, USA
| | - Helen A Shih
- Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Anita Mahajan
- Departments of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Paul D Brown
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota, USA
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Carbon Ion Radiotherapy: A Review of Clinical Experiences and Preclinical Research, with an Emphasis on DNA Damage/Repair. Cancers (Basel) 2017; 9:cancers9060066. [PMID: 28598362 PMCID: PMC5483885 DOI: 10.3390/cancers9060066] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Revised: 05/21/2017] [Accepted: 06/06/2017] [Indexed: 12/31/2022] Open
Abstract
Compared to conventional photon-based external beam radiation (PhXRT), carbon ion radiotherapy (CIRT) has superior dose distribution, higher linear energy transfer (LET), and a higher relative biological effectiveness (RBE). This enhanced RBE is driven by a unique DNA damage signature characterized by clustered lesions that overwhelm the DNA repair capacity of malignant cells. These physical and radiobiological characteristics imbue heavy ions with potent tumoricidal capacity, while having the potential for simultaneously maximally sparing normal tissues. Thus, CIRT could potentially be used to treat some of the most difficult to treat tumors, including those that are hypoxic, radio-resistant, or deep-seated. Clinical data, mostly from Japan and Germany, are promising, with favorable oncologic outcomes and acceptable toxicity. In this manuscript, we review the physical and biological rationales for CIRT, with an emphasis on DNA damage and repair, as well as providing a comprehensive overview of the translational and clinical data using CIRT.
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66
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Keta OD, Todorović DV, Bulat TM, Cirrone PGA, Romano F, Cuttone G, Petrović IM, Ristić Fira AM. Comparison of human lung cancer cell radiosensitivity after irradiations with therapeutic protons and carbon ions. Exp Biol Med (Maywood) 2017; 242:1015-1024. [PMID: 27633574 PMCID: PMC5444635 DOI: 10.1177/1535370216669611] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 08/23/2016] [Indexed: 12/05/2023] Open
Abstract
The aim of this study was to investigate effects of irradiations with the therapeutic proton and carbon ion beams in two non-small cell lung cancers, CRL5876 adenocarcinoma and HTB177 large cell lung carcinoma. The DNA damage response dynamics, cell cycle regulation, and cell death pathway activation were followed. Viability of both cell lines was lower after carbon ions compared to the therapeutic proton irradiations. HTB177 cells showed higher recovery than CRL5876 cells seven days following the treatments, but the survival rates of both cell lines were lower after exposure to carbon ions with respect to therapeutic protons. When analyzing cell cycle distribution of both CRL5876 and HTB177 cells, it was noticed that therapeutic protons predominantly induced G1 arrest, while the cells after carbon ions were arrested in G2/M phase. The results illustrated that differences in the levels of phosphorylated H2AX, a double-strand break marker, exist after therapeutic proton and carbon ion irradiations. We also observed dose- and time-dependent increase in the p53 and p21 levels after applied irradiations. Carbon ions caused larger increase in the quantity of p53 and p21 compared to therapeutic protons. These results suggested that various repair mechanisms were induced in the treated cells. Considering the fact that we have not observed any distinct change in the Bax/Bcl-2 ratio following irradiations, it seemed that different types of cell death were involved in the response to the two types of irradiations that were applied.
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Affiliation(s)
- Otilija D Keta
- Vinča Institute of Nuclear Sciences, University of Belgrade, Belgrade 11001, Serbia
| | | | - Tanja M Bulat
- Vinča Institute of Nuclear Sciences, University of Belgrade, Belgrade 11001, Serbia
| | - Pablo GA Cirrone
- Laboratori Nazionali del Sud, Instituto Nazionale di Fisica Nucleare, Catania 95123, Italy
| | - Francesco Romano
- Laboratori Nazionali del Sud, Instituto Nazionale di Fisica Nucleare, Catania 95123, Italy
| | - Giacomo Cuttone
- Laboratori Nazionali del Sud, Instituto Nazionale di Fisica Nucleare, Catania 95123, Italy
| | - Ivan M Petrović
- Vinča Institute of Nuclear Sciences, University of Belgrade, Belgrade 11001, Serbia
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67
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Grün R, Friedrich T, Krämer M, Scholz M. Systematics of relative biological effectiveness measurements for proton radiation along the spread out Bragg peak: experimental validation of the local effect model. Phys Med Biol 2017; 62:890-908. [PMID: 28072575 DOI: 10.1088/1361-6560/62/3/890] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The purpose of this study is to compare the predictions of the local effect model (LEM) in an extensive analysis to proton relative biological effectiveness (RBE) experiments found in the literature, and demonstrate the capabilities of the model as well as to discuss potential limitations. 19 publications with in vitro experiments and 10 publications with in vivo experiments focusing on proton RBE along the spread out Bragg peak (SOBP) were considered. In total the RBE values of over 100 depth positions were compared to LEM predictions. The treatment planning software TRiP98 was used to reconstruct the proton depth dose profile, and, together with the physical dose distribution, the RBE prediction was conducted based on the LEM. Only parameters from photon dose response curves are used as input for the LEM, and no free parameters are introduced, thus allowing us to demonstrate the predictive power of the LEM for protons. The LEM describes the RBE adequately well within the SOBP region with a relative deviation of typically less than 10% up to 10 keV µm-1. In accordance with previous publications a clear dependence of RBE on the dose-averaged linear energy transfer (LETD) was observed. The RBE in the experiments tends to increase above 1.1 for LETD values above 2 keV µm-1 and above 1.5 for LETD values higher than 10 keV µm-1 (distal part of the SOBP). The dose dependence is most pronounced for doses lower than 3 Gy (RBE). However, both the LEM predictions and experimental data show only a weak dependence of RBE on the tissue type, as characterized by the α/β ratio, which is considered insignificant with regard to the general uncertainties of RBE. The RBE predicted by the LEM shows overall very good agreement with the experimental data within the SOBP region and is in better agreement with the experimental data than the constant RBE of 1.1 that is currently applied in the clinics. All RBE trends deduced from the experiments were also reflected by the LEM predictions, which are purely based on input parameters derived from low-LET photon radiation.
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Affiliation(s)
- Rebecca Grün
- Department of Biophysics, GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany
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68
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Peeler CR, Mirkovic D, Titt U, Blanchard P, Gunther JR, Mahajan A, Mohan R, Grosshans DR. Clinical evidence of variable proton biological effectiveness in pediatric patients treated for ependymoma. Radiother Oncol 2016; 121:395-401. [PMID: 27863964 PMCID: PMC5450501 DOI: 10.1016/j.radonc.2016.11.001] [Citation(s) in RCA: 179] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 10/26/2016] [Accepted: 11/01/2016] [Indexed: 12/25/2022]
Abstract
BACKGROUND AND PURPOSE A constant relative biological effectiveness (RBE) is used for clinical proton therapy; however, experimental evidence indicates that RBE can vary. We analyzed pediatric ependymoma patients who received proton therapy to determine if areas of normal tissue damage indicated by post-treatment image changes were associated with increased biological dose effectiveness. MATERIAL AND METHODS Fourteen of 34 children showed T2-FLAIR hyperintensity on post-treatment magnetic resonance (MR) images. We delineated regions of treatment-related change and calculated dose and linear energy transfer (LET) distributions with Monte Carlo. Voxel-level image change data were fit to a generalized linear model incorporating dose and LET. Cross-validation was used to determine model parameters and for receiver operating characteristic curve analysis. Tolerance dose (TD50; dose at which 50% of patients would experience toxicity) was interpolated from the model. RESULTS Image changes showed dependence on increasing LET and dose. TD50 decreased with increasing LET, indicating an increase in biological dose effectiveness. The cross-validated area under the curve for the model was 0.91 (95% confidence interval 0.88-0.94). CONCLUSIONS Our correlation of changes on MR images after proton therapy with increased LET constitutes the first clinical evidence of variable proton biological effectiveness.
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Affiliation(s)
- Christopher R Peeler
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, United States; The University of Texas Graduate School of Biomedical Sciences at Houston, United States
| | - Dragan Mirkovic
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, United States
| | - Uwe Titt
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, United States
| | - Pierre Blanchard
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, United States; Gustave Roussy, Université Paris-Saclay, Department of Radiation Oncology, Villejuif, France
| | - Jillian R Gunther
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, United States
| | - Anita Mahajan
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, United States
| | - Radhe Mohan
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, United States
| | - David R Grosshans
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, United States.
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McFadden CH, Hallacy TM, Flint DB, Granville DA, Asaithamby A, Sahoo N, Akselrod MS, Sawakuchi GO. Time-Lapse Monitoring of DNA Damage Colocalized With Particle Tracks in Single Living Cells. Int J Radiat Oncol Biol Phys 2016; 96:221-7. [DOI: 10.1016/j.ijrobp.2016.04.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 04/08/2016] [Indexed: 12/18/2022]
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Bretscher HS, Fox DT. Proliferation of Double-Strand Break-Resistant Polyploid Cells Requires Drosophila FANCD2. Dev Cell 2016; 37:444-57. [PMID: 27270041 PMCID: PMC4901310 DOI: 10.1016/j.devcel.2016.05.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 02/22/2016] [Accepted: 05/02/2016] [Indexed: 12/17/2022]
Abstract
Conserved DNA-damage responses (DDRs) sense genome damage and prevent mitosis of broken chromosomes. How cells lacking DDRs cope with broken chromosomes during mitosis is poorly understood. DDRs are frequently inactivated in cells with extra genomes (polyploidy), suggesting that study of polyploidy can reveal how cells with impaired DDRs/genome damage continue dividing. Here, we show that continued division and normal organ development occurs in polyploid, DDR-impaired Drosophila papillar cells. As papillar cells become polyploid, they naturally accumulate broken acentric chromosomes but do not apoptose/arrest the cell cycle. To survive mitosis with acentric chromosomes, papillar cells require Fanconi anemia proteins FANCD2 and FANCI, as well as Blm helicase, but not canonical DDR signaling. FANCD2 acts independently of previous S phases to promote alignment and segregation of acentric DNA produced by double-strand breaks, thus avoiding micronuclei and organ malformation. Because polyploidy and impaired DDRs can promote cancer, our findings provide insight into disease-relevant DNA-damage tolerance mechanisms.
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Affiliation(s)
- Heidi S Bretscher
- Department of Pharmacology & Cancer Biology, Duke University School of Medicine, DUMC Box 3813, Durham, NC 27710, USA
| | - Donald T Fox
- Department of Pharmacology & Cancer Biology, Duke University School of Medicine, DUMC Box 3813, Durham, NC 27710, USA.
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Underwood T, Paganetti H. Variable Proton Relative Biological Effectiveness: How Do We Move Forward? Int J Radiat Oncol Biol Phys 2016; 95:56-58. [DOI: 10.1016/j.ijrobp.2015.10.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 10/01/2015] [Indexed: 12/26/2022]
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Baumann M, Krause M, Overgaard J, Debus J, Bentzen SM, Daartz J, Richter C, Zips D, Bortfeld T. Radiation oncology in the era of precision medicine. Nat Rev Cancer 2016; 16:234-49. [PMID: 27009394 DOI: 10.1038/nrc.2016.18] [Citation(s) in RCA: 512] [Impact Index Per Article: 64.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Technological advances and clinical research over the past few decades have given radiation oncologists the capability to personalize treatments for accurate delivery of radiation dose based on clinical parameters and anatomical information. Eradication of gross and microscopic tumours with preservation of health-related quality of life can be achieved in many patients. Two major strategies, acting synergistically, will enable further widening of the therapeutic window of radiation oncology in the era of precision medicine: technology-driven improvement of treatment conformity, including advanced image guidance and particle therapy, and novel biological concepts for personalized treatment, including biomarker-guided prescription, combined treatment modalities and adaptation of treatment during its course.
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Affiliation(s)
- Michael Baumann
- Department of Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden
- OncoRay - National Center for Radiation Research in Oncology (NCRO), Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, and Helmholtz-Zentrum Dresden-Rossendorf, Fetscherstrasse 74, 01307 Dresden
- National Center for Tumor Diseases (NCT), Fetscherstrasse 74, 01307 Dresden
- German Cancer Consortium (DKTK) Dresden, Germany
- German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Oncology, Bautzner Landstrasse 400, 01328 Dresden, Germany
| | - Mechthild Krause
- Department of Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden
- OncoRay - National Center for Radiation Research in Oncology (NCRO), Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, and Helmholtz-Zentrum Dresden-Rossendorf, Fetscherstrasse 74, 01307 Dresden
- National Center for Tumor Diseases (NCT), Fetscherstrasse 74, 01307 Dresden
- German Cancer Consortium (DKTK) Dresden, Germany
- German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Oncology, Bautzner Landstrasse 400, 01328 Dresden, Germany
| | - Jens Overgaard
- Department of Experimental Clinical Oncology, Aarhus University Hospital, Nørrebrogade 44, 8000 Aarhus C, Denmark
| | - Jürgen Debus
- German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
- Heidelberg Institute of Radiation Oncology (HIRO), National Center for Radiation Research in Oncology (NCRO), University of Heidelberg Medical School and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
- National Center for Tumor Diseases (NCT), Im Neuenheimer Feld 460, 69120 Heidelberg
- Heidelberg Ion Therapy Center (HIT), Department of Radiation Oncology, University of Heidelberg Medical School, Im Neuenheimer Feld 400, 69120 Heidelberg
- German Cancer Consortium (DKTK) Heidelberg, Germany
| | - Søren M Bentzen
- Department of Epidemiology and Public Health and Greenebaum Cancer Center, University of Maryland School of Medicine, 22 S Greene Street S9a03, Baltimore, Maryland 21201, USA
| | - Juliane Daartz
- Department of Radiation Oncology, Physics Division, Massachusetts General Hospital and Harvard Medical School, 1000 Blossom Street Cox 362, Boston, Massachusetts 02114, USA
| | - Christian Richter
- Department of Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden
- OncoRay - National Center for Radiation Research in Oncology (NCRO), Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, and Helmholtz-Zentrum Dresden-Rossendorf, Fetscherstrasse 74, 01307 Dresden
- National Center for Tumor Diseases (NCT), Fetscherstrasse 74, 01307 Dresden
- German Cancer Consortium (DKTK) Dresden, Germany
- German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Daniel Zips
- German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
- German Cancer Consortium Tübingen, Postfach 2669, 72016 Tübingen
- Department of Radiation Oncology, Faculty of Medicine and University Hospital Tübingen, Eberhard Karls Universität Tübingen, Hoppe-Seyler-Strasse 3, 72016 Tübingen, Germany
| | - Thomas Bortfeld
- Department of Radiation Oncology, Physics Division, Massachusetts General Hospital and Harvard Medical School, 1000 Blossom Street Cox 362, Boston, Massachusetts 02114, USA
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Held KD, Kawamura H, Kaminuma T, Paz AES, Yoshida Y, Liu Q, Willers H, Takahashi A. Effects of Charged Particles on Human Tumor Cells. Front Oncol 2016; 6:23. [PMID: 26904502 PMCID: PMC4751258 DOI: 10.3389/fonc.2016.00023] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 01/21/2016] [Indexed: 12/22/2022] Open
Abstract
The use of charged particle therapy in cancer treatment is growing rapidly, in large part because the exquisite dose localization of charged particles allows for higher radiation doses to be given to tumor tissue while normal tissues are exposed to lower doses and decreased volumes of normal tissues are irradiated. In addition, charged particles heavier than protons have substantial potential clinical advantages because of their additional biological effects, including greater cell killing effectiveness, decreased radiation resistance of hypoxic cells in tumors, and reduced cell cycle dependence of radiation response. These biological advantages depend on many factors, such as endpoint, cell or tissue type, dose, dose rate or fractionation, charged particle type and energy, and oxygen concentration. This review summarizes the unique biological advantages of charged particle therapy and highlights recent research and areas of particular research needs, such as quantification of relative biological effectiveness (RBE) for various tumor types and radiation qualities, role of genetic background of tumor cells in determining response to charged particles, sensitivity of cancer stem-like cells to charged particles, role of charged particles in tumors with hypoxic fractions, and importance of fractionation, including use of hypofractionation, with charged particles.
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Affiliation(s)
- Kathryn D Held
- Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School , Boston, MA , USA
| | - Hidemasa Kawamura
- Gunma University Heavy Ion Medical Center, Gunma, Japan; Department of Radiation Oncology, Gunma University Graduate School of Medicine, Gunma, Japan
| | - Takuya Kaminuma
- Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA; Gunma University Heavy Ion Medical Center, Gunma, Japan; Department of Radiation Oncology, Gunma University Graduate School of Medicine, Gunma, Japan
| | | | - Yukari Yoshida
- Gunma University Heavy Ion Medical Center , Gunma , Japan
| | - Qi Liu
- Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School , Boston, MA , USA
| | - Henning Willers
- Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School , Boston, MA , USA
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Granville DA, Sahoo N, Sawakuchi GO. Simultaneous measurements of absorbed dose and linear energy transfer in therapeutic proton beams. Phys Med Biol 2016; 61:1765-79. [DOI: 10.1088/0031-9155/61/4/1765] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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75
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Liu Q, Underwood TSA, Kung J, Wang M, Lu HM, Paganetti H, Held KD, Hong TS, Efstathiou JA, Willers H. Disruption of SLX4-MUS81 Function Increases the Relative Biological Effectiveness of Proton Radiation. Int J Radiat Oncol Biol Phys 2016; 95:78-85. [PMID: 27084631 DOI: 10.1016/j.ijrobp.2016.01.046] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 11/20/2015] [Accepted: 01/25/2016] [Indexed: 12/25/2022]
Abstract
PURPOSE Clinical proton beam therapy has been based on the use of a generic relative biological effectiveness (RBE) of ∼1.1. However, emerging data have suggested that Fanconi anemia (FA) and homologous recombination pathway defects can lead to a variable RBE, at least in vitro. We investigated the role of SLX4 (FANCP), which acts as a docking platform for the assembly of multiple structure-specific endonucleases, in the response to proton irradiation. METHODS AND MATERIALS Isogenic cell pairs for the study of SLX4, XPF/ERCC1, MUS81, and SLX1 were irradiated at the mid-spread-out Bragg peak of a clinical proton beam (linear energy transfer 2.5 keV/μm) or with 250 kVp x-rays, and the clonogenic survival fractions were determined. To estimate the RBE of the protons relative to cobalt-60 photons (Co60Eq), we assigned a RBE(Co60Eq) of 1.1 to x-rays to correct the physical dose measured. Standard DNA repair foci assays were used to monitor the damage responses, and the cell cycle distributions were assessed by flow cytometry. The poly(ADP-ribose) polymerase inhibitor olaparib was used for comparison. RESULTS Loss of SLX4 function resulted in an enhanced proton RBE(Co60Eq) of 1.42 compared with 1.11 for wild-type cells (at a survival fraction of 0.1; P<.05), which correlated with increased persistent DNA double-strand breaks in cells in the S/G2 phase. Genetic analysis identified the SLX4-binding partner MUS81 as a mediator of resistance to proton radiation. Both proton irradiation and olaparib treatment resulted in a similar prolonged accumulation of RAD51 foci in SLX4/MUS81-deficient cells, suggesting a common defect in the repair of DNA replication fork-associated damage. CONCLUSIONS A defect in the FA pathway at the level of SLX4 results in hypersensitivity to proton radiation, which is, at least in part, due to impaired MUS81-mediated processing of replication forks that stall at clustered DNA damage. In vivo and clinical studies are needed to confirm these findings in human cancers.
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Affiliation(s)
- Qi Liu
- Laboratory of Cellular and Molecular Radiation Oncology, Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts
| | - Tracy S A Underwood
- Division of Radiation Physics, Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts
| | - Jong Kung
- Division of Radiation Physics, Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts
| | - Meng Wang
- Laboratory of Cellular and Molecular Radiation Oncology, Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts
| | - Hsiao-Ming Lu
- Division of Radiation Physics, Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts
| | - Harald Paganetti
- Division of Radiation Physics, Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts
| | - Kathryn D Held
- Laboratory of Cellular and Molecular Radiation Oncology, Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts
| | - Theodore S Hong
- Laboratory of Cellular and Molecular Radiation Oncology, Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts
| | - Jason A Efstathiou
- Laboratory of Cellular and Molecular Radiation Oncology, Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts
| | - Henning Willers
- Laboratory of Cellular and Molecular Radiation Oncology, Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts.
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76
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McNamara AL, Schuemann J, Paganetti H. A phenomenological relative biological effectiveness (RBE) model for proton therapy based on all published in vitro cell survival data. Phys Med Biol 2015; 60:8399-416. [PMID: 26459756 DOI: 10.1088/0031-9155/60/21/8399] [Citation(s) in RCA: 209] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Proton therapy treatments are currently planned and delivered using the assumption that the proton relative biological effectiveness (RBE) relative to photons is 1.1. This assumption ignores strong experimental evidence that suggests the RBE varies along the treatment field, i.e. with linear energy transfer (LET) and with tissue type. A recent review study collected over 70 experimental reports on proton RBE, providing a comprehensive dataset for predicting RBE for cell survival. Using this dataset we developed a model to predict proton RBE based on dose, dose average LET (LETd) and the ratio of the linear-quadratic model parameters for the reference radiation (α/β)x, as the tissue specific parameter. The proposed RBE model is based on the linear quadratic model and was derived from a nonlinear regression fit to 287 experimental data points. The proposed model predicts that the RBE increases with increasing LETd and decreases with increasing (α/β)x. This agrees with previous theoretical predictions on the relationship between RBE, LETd and (α/β)x. The model additionally predicts a decrease in RBE with increasing dose and shows a relationship between both α and β with LETd. Our proposed phenomenological RBE model is derived using the most comprehensive collection of proton RBE experimental data to date. Previously published phenomenological models, based on a limited data set, may have to be revised.
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Affiliation(s)
- Aimee L McNamara
- Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, 30 Fruit Street, Boston, MA 02114, USA
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Willers H, Gheorghiu L, Liu Q, Efstathiou JA, Wirth LJ, Krause M, von Neubeck C. DNA Damage Response Assessments in Human Tumor Samples Provide Functional Biomarkers of Radiosensitivity. Semin Radiat Oncol 2015; 25:237-50. [PMID: 26384272 DOI: 10.1016/j.semradonc.2015.05.007] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Predictive biomarkers are urgently needed for individualization of radiation therapy and treatment with radiosensitizing anticancer agents. Genomic profiling of human cancers provides us with unprecedented insight into the mutational landscape of genes directly or indirectly involved in the response to radiation-induced DNA damage. However, to what extent this wealth of structural information about the cancer genome produces biomarkers of sensitivity to radiation remains to be seen. Investigators are increasingly studying the subnuclear accumulation (ie, foci) of proteins in the DNA damage response (DDR), such as gamma-H2AX, 53BP1, or RAD51, as a surrogate of treatment sensitivity. Recent findings from preclinical studies have demonstrated the predictive potential of DDR foci by correlating foci with clinically relevant end points such as tumor control probability. Therefore, preclinical investigations of DDR foci responses are increasingly moving into cells and tissues from patients, which is the major focus of this review. The advantage of using DDR foci as functional biomarkers is that they can detect alterations in DNA repair due to various mechanisms. Moreover, they provide a global measurement of DDR network function without needing to know the identities of all the components, many of which remain unknown. Foci assays are thus expected to yield functional insight that may complement or supersede genomic information, thereby giving radiation oncologists unique opportunities to individualize cancer treatments in the near future.
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Affiliation(s)
- Henning Willers
- Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA.
| | - Liliana Gheorghiu
- Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA
| | - Qi Liu
- Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA
| | - Jason A Efstathiou
- Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA
| | - Lori J Wirth
- Department of Medicine, Massachusetts General Hospital, Boston, MA
| | - Mechthild Krause
- German Cancer Consortium (DKTK) Dresden and German Cancer Research Center (DKFZ), Heidelberg, Germany; Department of Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Germany; OncoRay-National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Germany; Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology, Germany
| | - Cläre von Neubeck
- OncoRay-National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Germany
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