Treatment results of fast neutron irradiation in soft tissue sarcomas

Purpose

Surgery is the standard treatment of soft-tissue sarcomas. Adjuvant radiotherapy with photons after less radical resection can improve local control. The rate of tumor control achieved in patients with G1 and G2 soft tissue sarcomas incompletely resected and treated postoperatively with neutron irradiation is similar to that seen in patients undergoing complete tumor resection and adjuvant photon irridiation.

Patients and Methods

At the Department of Radiotherapy and Radiation Oncology of the University of Münster, 61 patients with soft tissue sarcomas were irradiated postoperatively with fast neutrons. Mainly tumors of low or intermediate malignancy (R0; 27%; R1, 21%; R2, 52%) were treated. Malignant fibrous histiocytoma, liposarcoma, and neurogenic sarcomas dominated. 46 patients were irradiated with fast neutrons alone, and 15 patients were treated with mixed beam therapy (photons and neutrons).

Results

The median follow-up period was 44 months. Overall five-year survival probability analysed by Kaplan-Meyer method was 42.5%. The local control rate was 57.7%. 15 patients showed complete remission, 18 patients had a partial remission. Only 11% of the patients showed grade III and IV side effects during neutron irradiation.

Conclusion

Neutron irradiation is efficocious in treating highly and intermediately differentiated soft tissue sarcomas. The result of surgical resection seems to be a very important prognostic factor for patients with soft tissue sarcomas.