Patients with microscopically complete excision for invasive disease followed by whole-breast irradiation of 50 Gy in 5 weeks were centrally randomised ( 1:1 ) with a minimisation algorithm to receive 16 Gy boost or no boost , with minimisation for age , menopausal status , presence of extensive ductal carcinoma in situ , clinical tumour size , nodal status , and institution .