Postmastectomy chest wall radiotherapy for breast cancer (SUPREMO): 5-year quality-of-life results from a randomised, controlled, phase 3 trial

BACKGROUND: The SUPREMO trial reported adjuvant chest wall radiotherapy had no effect on 10-year overall survival (primary endpoint) in patients with intermediate-risk breast cancer after mastectomy. The quality of life (QOL) substudy of SUPREMO (UK patients only) examines the effects of chest wall radiotherapy in patients with intermediate-risk breast cancer 1 year, 2 years, 5 years, and 10 years after treatment. Here, we report 5-year QOL results (a secondary endpoint), including prespecified subgroup analyses. METHODS: SUPREMO is an international, parallel-group, randomised, controlled, phase 3 trial. Women aged 18 years or older with intermediate-risk breast cancer (defined as pT1-2N1 or pT3N0 or pT2N0 with histological grade 3, or lymphovascular invasion, or both) who had undergone mastectomy (and axillary surgery) were randomly assigned (1:1) to receive chest wall radiotherapy (40-50 Gy in 15-25 fractions) or no radiotherapy. Randomisation was in permuted blocks with varying block length, stratified by centre, without masking of patients or investigators. All UK patients were invited to the QOL substudy. Consenting patients completed validated questionnaires (European Organisation for Research and Treatment of Cancer Quality of Life Core 30-item questionnaire; European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Breast Cancer Module, 23 items; Body Image Scale; and Hospital Anxiety and Depression Scale) before randomisation and at 1 year, 2 years, 5 years, and 10 years. Here, we report the prespecified primary QOL outcomes of global QOL, fatigue, physical function, chest wall symptoms, shoulder and arm symptoms, body image, anxiety, and depression in the intention to treat population, using repeated measures mixed-effects models. This trial is registered with the ISRCTN registry, ISRCTN61145589 and is now completed. FINDINGS: Between Aug 4, 2006, and April 29, 2013, SUPREMO recruited 1691 patients internationally, of whom 1679 were randomly assigned to receive chest wall radiotherapy (n=845) or not (n=834). Of 1233 patients from UK centres (619 in the chest wall radiotherapy group and 614 in the no chest wall radiotherapy group), 989 (80%) consented to the QOL substudy: 947 (96%) of 989 returned baseline questionnaires and 620 (75%) of 832 patients returned the expected year-5 questionnaires. Chest wall symptoms were worse with chest wall radiotherapy (effect estimate 1·99 [95% CI 0·36-3·62]; p=0·017) with an improvement between years 1, 2, and 5. Chemotherapy was associated with less improvement over time (effect estimate 2·97 [95% CI 0·24-5·71]; p=0·033) but without interaction with chest wall radiotherapy. No statistically significant differences were observed in other QOL domains (arm symptoms, body image, fatigue, pain, overall QOL, physical functioning, or anxiety and depression). In the subgroup analyses, patients who had a sentinel lymph node biopsy followed up by an axillary lymph node clearance with chest wall radiotherapy had worse chest wall symptoms than those having a single axillary operation (difference chest wall radiotherapy vs no chest wall radiotherapy -5·29 [95%CI -8·53 to -2·05]; p=0·0015). INTERPRETATION: The 5-year QOL findings showed worse chest wall toxicity and no effect on other QOL domains. The subgroup analyses suggested a potential negative effect of chemotherapy and axillary clearance after sentinel node biopsy. FUNDING: UK Medical Research Council, National Institute for Health and Care Research, European Organisation for Research and Treatment of Cancer, Edinburgh Trustees of Breast Cancer Institute in Edinburgh and the Edinburgh Cancer Centre NHS Endowment funds, The Dutch Cancer Society, Trustees of the Hong Kong and Shanghai Banking Corporation.