Median overall survival was 28.7 months ( 95 % CI 24.1-36 .9 ) for patients who received standard-dose radiotherapy and 20.3 months ( 17.7-25 .0 ) for those who received high-dose radiotherapy ( hazard ratio [ HR ] 1.38 , 95 % CI 1.09-1 .76 ; p = 0.004 ) .