Neutron and neutron-boost irradiation of soft tissue sarcomas: a 4.5 year analysis of 139 patients.

A 4.5 year analysis of neutron and neutron-boost therapy is presented for 139 patients with soft tissue sarcomas. The actuarial survival rate of all patients is 64.3%, the disease-free survival rate is 61.6%. Significant differences in local control rates were found as a function of tumour stage (100% for T1, 72% for T2 and 46% for T3; p: 0.018) and as a function of the presence (50.5%) or absence of clinical evidence of tumour at the time of irradiation (76%; p: 0.002). The corresponding actuarial survival rates are 90.1% for T1 tumours, 78.5% for T2 tumours and 51.2% for T3 tumours, and on the other hand, 50.5% for patients with gross tumour and 76% for patients with no clinical evidence of tumour. A rather high morbidity rate (31/111, i.e. 28%) was observed after full neutron treatment. In order to reduce this complication rate, a combination of photons and a neutron boost was adopted. On 28 patients treated up to now, only two severe complications were observed. The effectiveness of this treatment regimen is presently being evaluated in a prospective European Organization for Research on Treatment of Cancer (EORTC) trial.