High volume Low volume HORRAD STAMPEDE Failure-free survival Progression-free survival HORRAD12 STAMPEDE11 Overall survival Trial name Outcome and 151/177 23/39 355/405 230/387 124/177 13/39 304/405 179/387 119/177 12/39 222/405 101/387 events/patients RT+ADT 165/181 22/35 364/416 284/385 129/181 16/35 300/416 188/385 124/181 15/35 217/416 120/385 ADT Favours .5 1 2 p=0.003 1.40 (1.12, 1.74) 1.10 (0.58, 2.09) 1.44 (1.14, 1.82) p=0.054 1.28 (1.00, 1.64) 1.96 (0.88, 4.38) 1.22 (0.94, 1.59) p=0.017 1.44 (1.07, 1.95) 1.98 (0.86, 4.53) 1.38 (1.00, 1.90) HR (95% CI) Interaction 100.00 11.60 88.40 9.63 90.37 13.21 86.79 Weight % Greater treatment effect with higher Volume of disease with lower Supplementary Figure 2: (Exploratory) Effect of adding prostate radiotherapy to ADT on overall survival, progression-free survival and failure-free survival by volume of disease