Results of neutron therapy of soft-tissue sarcomas.

82 radioresistant mesenchymal sarcomas localized mainly at the trunk and the extremities have been irradiated with fast neutrons. In all three tumor dose ranges applied (6 to 9.6, 10 to 12.6, and 13 to 19 Gy) alike with 90% of the tumors either complete (congruent to 50%) or partial (congruent to 40%) regressions were observed; only 10% were unresponsive. Further 53 soft tissue sarcomas, showing a spontaneous recurrence rate following local extirpation up to 50%, underwent postoperative prophylactic irradiation with tumor doses of about 10 Gy. In 45 cases surveyed for at least two years, there developed seven (15%) recurrences in the irradiation field. The high regression rate and the good prophylactic effect against recurrences with doses well tolerable, render neutron radiation especially suitable for the treatment of soft tissue sarcomas.