Clinical Outcomes of Palliative Radiotherapy for Breast Lesions in Symptomatic Advanced Breast Cancer: A Decade of Experience at a Regional Tertiary Hospital

Background/Objectives: Palliative radiotherapy (RT) to the breast or chest wall is an effective option for symptom relief in advanced or metastatic breast cancer. However, real-world data on clinical outcomes, prognostic factors, and optimal RT dose and timing in the modern systemic therapy era remain limited. This study aimed to evaluate the efficacy of palliative breast RT and explore the optimal integration of systemic therapy with RT. Methods: We retrospectively reviewed 38 patients treated with palliative RT between 2015 and 2024 at a regional tertiary center. The median gross tumor volume (GTV) dose was 50 Gy (range, 30-62.5 Gy), corresponding to a median biologically effective dose (BED) to the GTV (α/β = 4) of 78.9 Gy. Treatment response, symptom relief, toxicity, and survival outcomes were analyzed. Results: With a median follow-up of 9.5 months, median overall survival (OS) was 12.8 months. 1- and 2-year in-field local control (LC) rates were both 79.6%. In a parsimonious multivariate analysis, ≥3 prior lines of systemic therapy (HR 3.500, 95% CI 1.278-9.590, p = 0.015) was independently associated with worse OS, whereas use of SIB or GTV boost was associated with improved OS (HR 0.351, 95% CI 0.145-0.848, p = 0.020). Higher planning target volume (PTV)-BED (α/β = 4) correlated with improved LC (HR 0.909, 95% CI 0.839-0.985, p = 0.019). Symptom relief within 3 months occurred in 82%. Treatment-related toxicities were generally mild, with no grade ≥ 4 acute or grade ≥ 2 late toxicities observed. Conclusions: Palliative breast RT achieved durable local control and effective symptom palliation with acceptable toxicity. Dose-tailored RT and earlier integration within the disease course may optimize outcomes in selected patients.