Incidence of sarcoma in patients treated with fast neutrons

Purpose: The aim of this study is to report the incidence of soft tissue sarcoma in a large group of patients treated with fast neutrons.

Methods: A systematic review was conducted of long-term follow-up after trials of fast neutron therapy for cancers at various sites. The study took place at Edinburgh Cancer Centre, Western General Hospital, Edinburgh, Scotland, United Kingdom. From 1977 to 1984, 620 patients were treated using fast neutrons in the MRC cyclotron unit in Edinburgh. Most of these were treated within randomized controlled trials. Follow-up was maintained in all except 2 patients, who left the area to return abroad. The main outcome measure was the incidence of new soft-tissue sarcomas during long-term follow-up.

Results: Three cases of sarcoma, developing within the treatment volume, were observed in a small group of patients treated some years earlier using fast neutrons. This incidence was 111 times what would have been expected in the normal population and 15 times the incidence in a comparable photon-treated group of patients.

Conclusion: The long-term incidence of sarcomas in patients previously treated with fast neutrons is significant.

Keywords:  Fast neutron therapy , Second tumor incidence , Sarcoma