Fast neutron therapy in treatment of soft tissue sarcoma--the Berlin-Buch study.

From 1975-1994, 221 adult patients with a total of 232 radiation sites for soft tissue sarcomas were irradiated with fast neutrons with a mean energy of 6.2 MeV in Berlin-Buch/Dresden-Rossendorf. The tumour dose ranged between 6 and 12 Gy and was limited by the low dose penetration of the neutron beam. A local control rate of 66% was obtained. The local control was affected by the tumour differentiation, residual status and histological subtype. Severe fibrosis of the subcutaneous tissues occurred in 40% usually after 2 years. No serious general side effects occurred. To optimize neutron therapy, a high energy clinically-based cyclotron with a fully rotational gantry and a multileaf collimator should be utilized. It seems that patients with locally advanced and well differentiated sarcomas can benefit from this therapy.