Patients were divided into 2 groups based on tumor Biological Effective Dose at 10 Gy ( BED 10 ) : those receiving standard dose ( SD ; n = 552 ) , consisting of 72Gy BED 10 76.8 Gy ( eg 60-64 Gy/30 -32 fractions [ fr ] ) , and those receiving intermediate dose ( ID ; n = 497 ) , consisting of 76.8 Gy < BED 10 < 100.8 Gy ( eg > 64 Gy/32 fr and < 74 Gy/37 fr ) , with lower-dose patients ( n = 225 ) excluded from consideration .