title: Bringing the heavy: carbon ion therapy in the radiobiological and clinical context.
abstract: Radiotherapy for the treatment of cancer is undergoing an evolution, shifting to the use of heavier ion species. For a plethora of malignancies, current radiotherapy using photons or protons yields marginal benefits in local control and survival. One hypothesis is that these malignancies have acquired, or are inherently radioresistant to low LET radiation. In the last decade, carbon ion radiotherapy facilities have slowly been constructed in Europe and Asia, demonstrating favorable results for many of the malignancies that do poorly with conventional radiotherapy. However, from a radiobiological perspective, much of how this modality works in overcoming radioresistance, and extending local control and survival are not yet fully understood. In this review, we will explain from a radiobiological perspective how carbon ion radiotherapy can overcome the classical and recently postulated contributors of radioresistance (α/β ratio, hypoxia, cell proliferation, the tumor microenvironment and metabolism, and cancer stem cells). Furthermore, we will make recommendations on the important factors to consider, such as anatomical location, in the future design and implementation of clinical trials. With the existing data available we believe that the expansion of carbon ion facilities into the United States is warranted.
authors.forename: Cody D
authors.initials: CD
authors.lastname: Schlaff
authors.forename: Andra
authors.initials: A
authors.lastname: Krauze
authors.forename: Arnaud
authors.initials: A
authors.lastname: Belard
authors.forename: John J
authors.initials: JJ
authors.lastname: O'Connell
authors.affiliation: Radiation Oncology Branch, National Cancer Institute, 10 Center Drive Magnuson Clinical Center Room B3B100, Bethesda, MD 20892, USA. camphauk@mail.nih.gov.
authors.forename: Kevin A
authors.initials: KA
authors.lastname: Camphausen
mesh_terms: D002244:Carbon / Q000737:chemistry*; D002453:Cell Cycle; D049109:Cell Proliferation; D002986:Clinical Trials as Topic; D005947:Glucose / Q000378:metabolism; D063193:Heavy Ion Radiotherapy / Q000379:methods*; D006801:Humans; D000860:Hypoxia; D018499:Linear Energy Transfer; D009369:Neoplasms / Q000378:metabolism / Q000532:radiotherapy*; D014411:Neoplastic Stem Cells / Q000166:cytology; D010100:Oxygen / Q000737:chemistry; D011878:Radiotherapy / Q000379:methods*; D013234:Stem Cells; D059016:Tumor Microenvironment
chemical_list: D002244:Carbon; D005947:Glucose; D010100:Oxygen