A small number of patients who had had mastectomy were recruited into the photographic substudy to validate the scoring method in patients who had chest wall radiotherapy, but are not reported here because photographs were only available for 76 patients. All patients who had breast conservation surgery were eligible for the photographic substudy at participating centres. For the patient-reported outcomes substudy all patients at participating centres were eligible. Concurrent endocrine therapy or trastuzumab, or both, were permitted but not concurrent chemotherapy.

All patients had axillary surgery (sentinel node biopsy or axillary dissection) nodal radiotherapy was not allowed in the main study.

A protocol amendment on Feb 15, 2013, excluded the lowest-risk patients (aged ≥65 years, pT1, grade 1 or 2, oestrogen receptor positive, HER2 negative, pN0, M0) to increase the overall primary event rate. InterpretationĮligible patients were women or men aged at least 18 years with invasive carcinoma of the breast (pT1–3, pN0–1, M0) following complete microscopic excision of the primary tumour by breast conservation surgery or mastectomy (reconstruction allowed), recruited in the UK from 47 radiotherapy centres and 50 referral centres. Patient and photographic assessments showed higher normal tissue effect risk for 27 Gy versus 40 Gy but not for 26 Gy versus 40 Gy.

Across all clinician assessments from 1–5 years, odds ratios versus 40 Gy in 15 fractions were 1♵5 (95% CI 1♳2 to 1♸3, p<0♰001) for 27 Gy in five fractions and 1♱2 (0♹4 to 1♳4, p=0♲0) for 26 Gy in five fractions. At 5 years, any moderate or marked clinician-assessed normal tissue effects in the breast or chest wall was reported for 98 of 986 (9♹%) 40 Gy patients, 155 (15♴%) of 1005 27 Gy patients, and 121 of 1020 (11♹%) 26 Gy patients. 5-year incidence of ipsilateral breast tumour relapse after 40 Gy was 2♱% (1♴ to 3♱) estimated absolute differences versus 40 Gy in 15 fractions were −0♳% (−1♰ to 0♹) for 27 Gy in five fractions (probability of incorrectly accepting an inferior five-fraction schedule: p=0♰022 vs 40 Gy in 15 fractions) and −0♷% (−1♳ to 0♳) for 26 Gy in five fractions (p=0♰0019 vs 40 Gy in 15 fractions). At a median follow-up of 71♵ months (IQR 71♳ to 71♷), the primary endpoint event occurred in 79 patients (31 in the 40 Gy group, 27 in the 27 Gy group, and 21 in the 26 Gy group) HRs versus 40 Gy in 15 fractions were 0♸6 (95% CI 0♵1 to 1♴4) for 27 Gy in five fractions and 0♶7 (0♳8 to 1♱6) for 26 Gy in five fractions. The Lancet Regional Health – Western Pacificīetween Nov 24, 2011, and June 19, 2014, we recruited and obtained consent from 4096 patients from 97 UK centres, of whom 1361 were assigned to the 40 Gy schedule, 1367 to the 27 Gy schedule, and 1368 to the 26 Gy schedule.The Lancet Regional Health – Southeast Asia.The Lancet Gastroenterology & Hepatology.

Speed compare stata 14 vs 15