Carbon Ion Radiotherapy for sacral chordoma: a systematic review of the literature

The aim of the present study is to describe the clinical outcomes and the incidence of complications related to Carbon Ion Radiotherapy (CIRT) in the treatment of sacral chordoma. Through a systematic review of published investigations on CIRT, we collected the local control rates (LC), the overall survival rates (OS) and the post-CIRT adverse effects. Afterwards, we calculated their weighted average, to have a broader perspective. PubMed/Medline and Google Scholar databases were searched to identify studies on Carbon Ion Radiotherapy as a treatment for sacral chordoma. We used Medical Subject Heading (MeSh) terms and keywords. We based our systematic review on the PRISMA guidelines. No data limitations were applied in the search on Pubmed/ Medline database; data limitation (from 2000 to 2019) was applied in the search on Google Scholar. Six studies were included in our review. Local control proportions reported in individual studies ranged between 77% and 96% (95% confidence interval), with respect to a 5-years follow-up. Overall survival rates ranged from 52% to 86% (95% confidence interval), with respect to a 5-years follow-up. Adverse CIRT-related events involving bone occurred in 7% of patients. Neurological and skin toxicities affected 20% and 5% of patients, respectively. Nowadays the gold standard of treatment for sacral chordoma is the surgical resection with wide margins. Whenever adequate oncological margins could not be achieved or could be achieved only by sacrificing neurological structures with consequent functional impairment, CIRT is an effective alternative which has been demonstrated to reach optimal local control and overall survival rate. The caregiver, anyway, should be aware of the potential adverse events and complications related to this kind of treatment.