In the intention-to-treat population , 118 ( 28 % ) patients allocated to 8 Gy treatment and 135 ( 32 % ) allocated to 20 Gy treatment had an overall pain response to treatment ( p = 021 ; response difference of 400 % [ upper limit of the 95 % CI 92 , less than the prespecified non-inferiority margin of 10 % ] ) .