Five relevant publications comprising one systematic review and meta-analysis, two non-randomized studies, and two economic evaluations were identified. Given the quantity and limited quality of available studies and the variety of outcomes of interest, the findings are inconclusive. Evidence of limited quality from one meta-analysis and one non-randomized study suggested that post-operative carbon ion beam radiation therapy provided better survival odds than post-operative conventional radiation therapy and similar odds as stereotactically-guided fractionated radiation therapy. Survival odds for CIRT relative to proton beam radiation therapy were similar up to 5 years following treatment but were worse at the 10-year follow-up time point. The evidence on adverse effects was limited, nonetheless the findings reinforce that carbon ion beam radiation therapy presents morbidity risks including sacral insufficiency fractures, hearing problems, cranial nerve deficit, abducent nerve paralysis, and double vision for patients with chordoma. Two economic evaluations conducted at one facility in Germany, found that post-operative carbon ion beam radiation therapy was cost-effective relative to post-operative conventional radiation therapy over a lifetime time horizon.No evidence-based guidelines were identified.