An analysis of the radiation related morbidity observed in a randomized trial of neutron therapy for XXXX .

@entity1 @entity150
This report is an analysis of the morbidity in the bladder and bowel observed in a randomized trial of d(15)+Be neutrons versus megavoltage photons in the treatment of @entity150 . Acute reactions in the bladder and bowel were significantly worse after photon therapy. Of the @entity1 treated with photons 45.7% had severe reactions in the bladder compared with 10.6% after neutron therapy (p less than 0.001). Severe acute bowel reactions were observed in 8.5% of the @entity1 after photon therapy compared with 3.8% after neutron therapy (p less than 0.05). Late reactions were significantly worse after neutrons. Severe late reactions in the bladder were seen in 58.5% of @entity1 after neutron therapy and in 40.5% after photon therapy (p less than 0.05). In the bowel they were observed in 53.3% of @entity1 after neutron therapy compared with 8% after photon therapy (p less than 0.0001). The disparity in the degree of early and late complications makes assessment of RBE values difficult. It is estimated that for bladder morbidity the RBE value, for photon dose fractions of 2.75 Gy, is less than 3.3 for early reactions and equal to 3.4 for late effects. The respective RBE values for early and late effects in the bowel are less than 3.4 and 3.8.
