A Cochrane review included 11 studies with a total of 2 343 subjects with a median follow up of 4.4 years. Postoperative radiotherapy (PORT) increased the risk of death (HR 1.18, 95% CI 1.07 to 1.31; 11 studies, n= 2343). This is equivalent to an overall reduction in survival from 58% to 53% at two years (an absolute detriment of 5% at two years, 95% CI 2% to 9%). Exploratory subgroup analyses suggested that this detrimental effect was most pronounced for patients with stage I/II, N0-N1 disease, whereas for stage III, N2 patients there was no clear evidence of an adverse effect.