Preliminary report of the M. D. Anderson Hospital/Texas A & M variable energy cyclotron fast-neutron therapy pilot study.

The records of 248 patients treated with fast neutrons and of 102 comparable but nonrandomized control patients treated conventionally with photons, surgery, or combined surgery and photon irradiation were reviewed. Fast neutron therapy included treatment with neutrons alone, a neutron boost after photon therapy, or a schedule of alternating neutron and photon treatments (mixed beam). The results with mixed beam irradiation were superior to those obtained with the other neutron therapy techniques, and compared favorably with the results of standard treatment methods. However, the lack of a conclusive advantage for neutron therapy in this pilot study illustrates the need for on-going randomized clinical trials.