Present status of fast neutron therapy in Asian countries

Fast neutron radiotherapy for primary mucosal melanomas of the head and neck

“…As a result, neutrons generate greater tumor cell kill compared to X‐rays. This translates into a therapeutic gain for a number of tumor types, including many typically radioresistant tumors that are poorly responsive to low linear energy transfer radiation, such as salivary gland tumors, sarcoma, and melanoma . Neutrons are also less dependent on tumor oxygenation and may be more effective in treating hypoxic tumors.…”

“…High linear energy transfer radiation is associated with increased relative biologic effectiveness compared to conventional X‐ray therapy. Neutrons have been reported to show a therapeutic gain for a number of tumor types, especially traditionally radioresistant tumors, such as salivary gland tumors, sarcoma, and melanoma …”

“…Neutrons have been reported to show a therapeutic gain for a number of tumor types, especially traditionally radioresistant tumors, such as salivary gland tumors, sarcoma, and melanoma. [17][18][19] We report our institutional experience with neutron therapy in patients with HNMM at the University of Washington.…”

Phase I/II clinical trials of carbon ion therapy for prostate cancer

“…Fast neutron beams exhibit high RBE and are expected to be more biologically effective against cancer cells. Clinical trials of fast neutron therapy for prostate cancer, including those of NIRS, have demonstrated favorable results [16,17]. A randomized trial comparing mixed-beam radiotherapy of fast neutrons and photons with 0 1 2 3 4 0 1 2 3 4 Total 54 3 2 1 3 60 14 12 2 14 66 3 3 1 3 2 1 1 7 72 5 3 3 2 3 1 5 11 72S a 1 2 1 2 3 66S a 52 5 36 18 3 57 Total 73 12 6 4 b 0 5 6 2 8 5 6 b 0 9 5…”

Neutron Radiation for Prostate Cancer

“…Seven patients required surgery for rectal injury, and two patients developed recto‐vesicle fistulas. At Chiba University, in Japan, 47 patients with locally advanced prostate cancer were treated between 1976 and 1986 with either neutron irradiation alone (36) or mixed‐beam irradiation ( 16). The local control rates at 3 years were 100%, 60%, and 52% for Stages A2, B, and C, respectively.…”