Analysis of neutron radiotherapy treatment complications.

A total of 6,345 patients have been entered in the RTOG particle registry since it was opened in 1980. Three hundred thirty of those patients were treated with neutrons alone for head and neck cancers, and 128 were treated with neutrons alone for pelvic cancers. The late normal Tissue Severe Toxicity (life-threatening and fatal) rates in the head and neck were 9% for high energy accelerators and 20% for low energy accelerators. The late normal Tissue Severe Toxicity rates in the pelvis were 4% for high energy accelerators and 39% with low energy accelerators.