Carbon ion radiotherapy in the treatment of gliomas: a review

Introduction: Gliomas are among the most common primary brain malignancies, with a poor prognosis for high grade gliomas despite aggressive therapy. Carbon ions, which exhibit favorable biological and physical characteristics, have recently been studied in intracranial malignancies as a way to escalate dose to the tumor while minimizing dose to normal tissue. Methods: Pubmed/Medline, SCOPUS, EMBASE, CINAHL and the Cochrane database were systematically reviewed using the search terms “carbon ion” and “glioma” or “glioblastoma” in August 2019. Out of 332 articles screened, 43 were included in this analysis. Results: This comprehensive review describes the pertinent physics and radiation biology studies relevant to the treatment of gliomas with carbon ions and summarizes the important clinical studies for both high and low grade gliomas. Studies investigating carbon ions as both definitive radiotherapy and as a boost to traditional radiotherapy are reviewed. The use of carbon ion radiotherapy in the setting of recurrent disease is also described. Conclusions: Carbon ion radiotherapy is both efficacious and safe based on early clinical studies. Current trials, including the CLEOPATRA and CINDERLLA trials, hope to define the role of carbon ion radiotherapy in the treatment of gliomas.