Biological effects of carbon ion radiation combined with chemotherapy

Carbon-ion beam (CIB) is a high-linear energy transfer (LET) radiation. CIB is featured with more superior physical dose distribution (i.e., Bragg Peak) as compared to photon beam. In addition, it induces more double-bond break thus has higher relative biological effectiveness (RBE) as compared to photon beam. The combined use of chemotherapy and conventional photon radiotherapy has been widely used in the treatment of tumors. Chemotherapy is used concurrently with photonradiotherapy due to its radiosensitization. However, the radiosensitization effect of chemotherapy used with carbon-ion radiotherapy is controversial. In this article, we reviewed the previous studies of biological effects of the combination of carbon ion radiotherapy and chemotherapy in basic biological studies (including cytological and animal experiments) and clinical outcomes, and elaborated the biological effects. Key words: Heavy ion; Radiotherapy; Chemotherapy