Clinical Results of Carbon Ion Radiotherapy at NIRS

Abstract

In 1994 a Phase I/II clinical study on carbon ion radiotherapy was begun at NIRS using HIMAC, which was then the world's only heavy ion accelerator complex dedicated to medical use in a hospital environment. Among several types of ion species, we have chosen carbon ions for cancer therapy because they had the most optimal properties in terms of possessing, both physically and biologically, the most effective dose-localization in the body. The purpose of the clinical study was to investigate the efficacy of carbon ion radiotherapy against a variety of tumors as well as to develop effective techniques for delivering an efficient dose to the tumor. The RBE of carbon ions was estimated to be 2.0 to 3.0 along the SOBP for acute skin reactions. As of August 2006, a total of 2,867 patients had been entered into Phase I/II or Phase II studies and analyzed for toxicity and local tumor response. The results have shown that carbon ion radiotherapy has the potential ability to provide a sufficient dose to the tumor with acceptable morbidity in the surrounding normal tissues. Tumors that appear to respond favorably to carbon ions include locally advanced tumors and those with histologically non-squamous cell type of tumors such as adenocarcinoma, adenoid cystic carcinoma, malignant melanoma, hepatoma, and bone/soft tissue sarcoma. By taking advantage of the biological and physical properties of high-LET radiation, the efficacy of treatment regimens with small fractions in short treatment times has been confirmed for almost all types of tumors in carbon ion radiotherapy.

Effects of Carbon Ion Beam on Putative Colon Cancer Stem Cells and Its Comparison with X-rays

“…Therefore, high LET heavy-ion therapy has several potential advantages over low LET photon therapy such as increased relative biological effect, reduced oxygen enhancement ratio, decreased cellcycle-dependent radiosensitivity, and induced complex DNA damage that is not easily repaired (5,6). Over the past decades, HIMAC has been successful in treating more than 5,000 cases of various human cancers and achieved promising clinical outcomes for many radioresistant tumor types, including recurrent colorectal cancer, hepatocellular carcinoma, chondroma, and sarcoma (7)(8)(9)(10).…”

Relative biological effectiveness in canine osteosarcoma cells irradiated with accelerated charged particles

“…In the present study, an in vitro comparison of the cell-killing effects of photons, protons and heavy ions on canine OSA cells was performed. For heavy ion irradiation, SOBP (spread out Bragg peak) carbon ions (LET at 50 keV/µm), which are used in radiotherapy, and iron ions (LET at 200 keV/µm), as above are expected to have maximum biological effects of heavy ions (23).…”

Upregulation of stress-response genes with cell cycle arrest induced by carbon ion irradiation in multiple murine tumors models

“…[1][2][3][4] Developments in radiation technology have lead to the clinical improvement of C-ion irradiation with well-localized energy distributions (high LET). While the development of high LET has a number of advantages over the more traditional radiation technology for the treatment of cancer, the mechanisms underlying the superior biological effectiveness of C-ion irradiation is not fully understood.…”