Oncology · Medical Literature
[Articles] Postmastectomy chest wall radiotherapy for breast cancer (SUPREMO): 5-year quality-of-life results from a randomised, controlled, phase 3 trial
Abstract
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.
Clinical relevance
In women with intermediate-risk breast cancer following mastectomy, does adjuvant chest wall radiotherapy adversely affect quality of life (QOL) at 5 years compared with no radiotherapy? __SNAPSHOT__ {"studyDesign":"Randomised, controlled, phase 3 trial (QOL substudy of the SUPREMO trial; UK patients only)","setting":"International multicentre trial; QOL substudy restricted to UK centres (multiple NHS hospitals across the UK, including Leeds, Edinburgh, Manchester, Sheffield, Belfast)","sampleSize":"Not reported in the available abstract for the 5-year QOL substudy specifically; overall SUPREMO trial enrolled approximately 1,600 patients","population":"Women aged ≥18 years with intermediate-risk breast cancer defined as pT1–2N1, pT3N0, or pT2N0 with histological grade 3 or lymphovascular invasion (or both), who had undergone mastectomy and axillary surgery","intervention":"Adjuvant chest wall radiotherapy (40–50 Gy in 15–25 fractions) following mastectomy","comparator":"No radiotherapy (observation with standard follow-up)","primaryOutcome":"Quality of life assessed via validated patient-reported outcome instruments: EORTC QLQ-C30, EORTC QLQ-BR23, Body Image Scale, and Hospital Anxiety and Depression Scale (HADS), evaluated at 1, 2, 5, and 10 years post-randomisation","followUp":"5 years (current report); longitudinal assessments also planned at 10 years","fundingSource":"Government/non-profit: UK Medical Research Council (MRC), National Institute for Health and Care Research (NIHR), European Organisation for Research and Treatment of Cancer (EORTC), Edinburgh Breast Cancer Institute Trustees, Edinburgh Cancer Centre NHS Endowment Funds, Dutch Cancer Society, Trustees of the Hong Kong and Shanghai Banking Corporation"}
Key findings
At 5 years, chest wall radiotherapy was associated with worse chest wall symptom scores compared with no radiotherapy. In a prespecified subgroup analysis, patients who underwent sentinel lymph node biopsy followed by axillary lymph node clearance and who received chest wall radiotherapy had significantly worse chest wall symptoms than those who had a single axillary operation (difference in chest wall radiotherapy vs no chest wall radiotherapy: –5.29; 95% CI –8.53 to –2.05; p=0.0015). No statistically significant differences between treatment groups were identified in any other QOL domain, including arm and shoulder symptoms, body image, fatigue, overall QOL, physical function, anxiety, or depression scores (consistent with findings at the 2-year timepoint). Subgroup analyses also suggested a potential negative interaction with receipt of chemotherapy on QOL outcomes, though specific effect sizes and p-values for the chemotherapy subgroup are not reported in the available abstract. NNH for chest wall symptom worsening is not calculable from abstract-level data. No novel safety signals beyond previously reported chest wall toxicity are described.
Practice implications
This 5-year QOL substudy of the SUPREMO trial establishes that adjuvant postmastectomy chest wall radiotherapy (CWRT) carries a persistent and statistically significant chest wall symptom burden relative to observation, extending findings previously observed at 2 years. Crucially, no meaningful adverse effect on global QOL, psychological well-being, body image, arm/shoulder function, or fatigue was detected, which is reassuring for patients who receive this treatment. The parent SUPREMO trial has already reported no significant improvement in 10-year overall survival from chest wall-only radiotherapy in this intermediate-risk population, meaning the risk–benefit calculus for CWRT in this group is now more clearly unfavourable on both efficacy and QOL grounds. The clinically important subgroup signals — worse chest wall toxicity in patients who underwent sentinel node biopsy followed by axillary clearance, and a potentially negative chemotherapy interaction — require cautious interpretation as hypothesis-generating findings only, given the known limitations of subgroup analyses. These results apply specifically to women with pT1–2N1, pT3N0, or selected pT2N0 disease treated between 2006 and 2013 with chest wall-only radiation (without systematic regional nodal irradiation), and should not be directly extrapolated to patients receiving modern postmastectomy radiotherapy that includes regional nodal volumes. Patients who would not meet current guidelines for CWRT (e.g., node-negative patients, those with single micrometastases) were included in SUPREMO and may further limit generalisability. Note that only the abstract is available; full data tables, including QOL score distributions, subgroup interaction p-values for chemotherapy, and compliance rates, are not reported here. __LIMITATIONS__ Only abstract-level data available; full statistical tables, compliance/missing data rates, and subgroup interaction p-values are not assessable.,QOL substudy restricted to UK patients only, potentially limiting international generalisability.,The trial enrolled patients between 2006 and 2013; systemic therapies (including HER2-targeted agents and CDK4/6 inhibitors), surgical techniques, and radiotherapy delivery have evolved substantially since then.,Chest wall-only radiotherapy was used in SUPREMO; modern PMRT typically encompasses regional nodal volumes (supraclavicular, internal mammary nodes), making direct applicability to contemporary practice limited.,Subgroup analyses (chemotherapy interaction; sentinel node biopsy plus axillary clearance) are exploratory and subject to type I error without formal correction for multiple comparisons.,Absence of blinding is inherent in a radiotherapy trial and may introduce patient-reported outcome bias.,The parent trial's primary survival endpoint showed no 10-year overall survival benefit, contextualising the QOL findings within a setting of uncertain oncologic efficacy.,The heterogeneous patient population included a substantial proportion who would not meet current PMRT indications, potentially diluting observed effects.,Loss to follow-up and questionnaire compliance at 5 years are not reported in the abstract and may affect the validity of QOL estimates. __BOTTOM_LINE_CATEGORY__ potentially_practice_informing __BOTTOM_LINE__ At 5 years, postmastectomy chest wall radiotherapy in intermediate-risk breast cancer patients results in persistent, statistically significant chest wall symptom worsening without benefit in any other QOL domain, complementing the parent trial's finding of no 10-year overall survival benefit. The observed worsening of chest wall toxicity in patients who underwent sentinel node biopsy followed by axillary clearance is an important hypothesis-generating signal that warrants consideration during multidisciplinary treatment planning. These findings support a shared decision-making approach in which the absence of demonstrated survival benefit and the documented chest wall QOL detriment are transparently communicated to patients with intermediate-risk disease, while recognising that SUPREMO's chest wall-only RT design and older patient cohort limit direct translation to current regional nodal irradiation practice.