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Postmastectomy Chest Wall Radiotherapy Worsens Chest Symptoms Without Broader QOL Impact at 5 Years
At 5-year follow-up, chest wall radiotherapy after mastectomy was associated with persistently worse chest wall symptoms compared with no radiotherapy, a statistically significant but modest difference (effect estimate 1.99, 95% CI 0.36–3.62, p=0.017), while no significant differences were detected across seven other quality-of-life domains. The overall picture is one of localised, measurable toxicity without broader functional or psychological detriment, though subgroup analyses identified patients at heightened risk of chest wall symptom burden.
What Was Studied
This report addresses whether adjuvant chest wall radiotherapy following mastectomy carries a meaningful quality-of-life (QOL) cost or benefit in women with intermediate-risk breast cancer. The primary QOL outcomes assessed at 5 years included global QOL, fatigue, physical function, chest wall symptoms, shoulder and arm symptoms, body image, anxiety, and depression — a comprehensive set of patient-reported endpoints designed to capture the full breadth of treatment-related impact.
How It Was Studied
SUPREMO is an international, parallel-group, randomised, controlled phase 3 trial that enrolled women aged 18 years or older with intermediate-risk breast cancer — defined as pT1–2N1, pT3N0, or pT2N0 with histological grade 3 disease, lymphovascular invasion, or both — who had undergone mastectomy and axillary surgery. A total of 1,679 patients were randomised 1:1 to receive chest wall radiotherapy (40–50 Gy in 15–25 fractions) or no radiotherapy. The QOL substudy was restricted to UK participants, of whom 989 consented to complete validated questionnaires — including the EORTC QLQ-C30, QLQ-BR23, Body Image Scale, and Hospital Anxiety and Depression Scale — at baseline and at 1, 2, 5, and 10 years. Data at the 5-year timepoint were available from 620 of 832 expected respondents (75%). Repeated-measures mixed-effects models were used in an intention-to-treat framework.
What Was Observed
- Chest wall symptoms were significantly worse in the radiotherapy group at 5 years. The effect estimate of 1.99 (95% CI 0.36–3.62, p=0.017) represents a small but statistically reliable increase in symptom burden, with some improvement observed progressively from year 1 through year 5, suggesting partial recovery over time rather than a static deficit.
- No statistically significant differences were found in seven other QOL domains. Arm symptoms, body image, fatigue, pain, overall QOL, physical functioning, and anxiety and depression were all comparable between the radiotherapy and no-radiotherapy groups at 5 years, indicating that the QOL impact of radiotherapy was largely confined to the chest wall.
- Chemotherapy was independently associated with less improvement in QOL over time. The effect estimate for this association was 2.97 (95% CI 0.24–5.71, p=0.033), though there was no statistically significant interaction between chemotherapy and chest wall radiotherapy, meaning the two treatments appeared to act independently on this outcome.
- A specific subgroup — patients who underwent sentinel lymph node biopsy followed by axillary lymph node clearance — experienced substantially worse chest wall symptoms when radiotherapy was added. The difference in chest wall symptoms between the radiotherapy and no-radiotherapy groups in this subgroup was –5.29 (95% CI –8.53 to –2.05, p=0.0015), a clinically meaningful signal suggesting that the combination of extensive axillary surgery and chest wall irradiation carries a compounded local toxicity burden.
Why This Matters
SUPREMO has already established that chest wall radiotherapy confers no survival advantage at 10 years in this intermediate-risk population. These 5-year QOL findings add an important dimension: the treatment imposes a measurable, persistent chest wall symptom burden without improving any other aspect of patient wellbeing. Identifying a subgroup — those who had axillary clearance after sentinel node biopsy — with disproportionately greater toxicity is particularly relevant for clinical decision-making in this setting.
How to Read This Result
This is a well-designed, high-quality phase 3 trial, but the QOL findings should be interpreted with caution given that the substudy was restricted to UK patients and that 25% of expected 5-year questionnaires were not returned, introducing the possibility of attrition bias; additionally, the absence of investigator or patient masking may have influenced self-reported symptom ratings.
Limitations
The QOL substudy enrolled only UK participants, which limits its generalisability to the broader international trial population. Attrition at the 5-year mark — with one in four expected questionnaires not returned — raises concern about whether those who did not respond differed systematically in their symptom experience. Finally, neither patients nor investigators were masked to treatment allocation, which could introduce reporting bias in subjective QOL assessments.