Although the formal criterion for stopping the trial was not met , the Data and Safety Monitoring Committee recommended study termination on ethical grounds based on the interaction ( two-sided P = 0.077 , hazard ratios for 74/75 : 0.23 / 0.72 ) between age and subgroup and treatment arm , which suggested that docetaxel may not represent an adequate control arm regimen for the age subgroup of 70-74 years .