Present status of fast neutron therapy in Asian countries

The present status of the treatment with fast neutrons performed in Asian countries is reviewed and the experiences with respect to the radiobiological indications are presentated and discussed. There are three facilities under operation, the National Institute of Radiological Sciences (NIRS) in Chiba, the Institute of Medical Science (IMS) in Tokyo and the Korea Cancer Center Hospital (KCCH) in Seoul. The clinical experiences can be summarized as follows: Fast neutrons are the treatment of choice for carcinoma of the salivary gland, Pancoast tumor of the lung, osteosarcoma, soft tissue sarcoma and malignant melanoma. Provided the isodose planning can be improved, it seems that also squamous cell carcinoma of the head and neck and esophagus, adenocarcinoma of the lung, stage I and prostatic adenocarcinoma can be benefit from neutron therapy. The same holds for malignant meningioma, while the benefit for glioblastoma multiforme has not yet been confirmed. Studies are going on for the treatment of other cancers and for evaluating the possible role of neutron therapy in combination with surgery.