S203
Clinical - Breast
ESTRO 2026
Digital Poster 238
Ultrahypofractionated vs hypofractionated palliative radiotherapy for inoperable or metastatic breast cancer Hiu Ching Wong, Brian Chan, Winnie Wing Yan Tin, Jean Ngan Sum Cheng, Ting Ying Ng, Frank Chi Sing Wong Department of Clinical Oncology, Tuen Mun Hospital, New Territories, Hong Kong Purpose/Objective: The aim of this study is to compare the local control and toxicity of different palliative breast radiotherapy regimens, using ultrahypofractionated or hypofractionated (with or without dose escalation) schedules. Material/Methods: Patients with inoperable or metastatic breast cancer who received palliative radiotherapy (RT) to the breast at Tuen Mun Hospital (2020-2024) were included. Treatment consisted of RT to the breast for ≥ 5 fractions, either ultrahypofractionated (UHRT) 26Gy in 5 fractions or hypofractionated (HRT) for at least 39Gy in 13 fractions with or without tumour boost to BED ≥ 70Gy ( α / β =3.5). Results: 112 patients were included. 31 patients received UHRT using 26Gy/5Fr. 81 patients received HRT regimen, ranging from 39Gy/13Fr to 63Gy/21Fr. BED (UHRT vs HRT) was 64.6Gy and 89.1Gy (median) (range 70.6- 128.6) respectively. Median age was 72 (range 37-96) in UHRT and 60 years (range 32-89) in HRT. More patients in UHRT had poorer performance status (ECOG ≥ 2: 58.1% vs 27.2%). Both groups had >90% of patients with T3/4 disease. Median tumor size was 7cm (range 1.5-18) in UHRT and 6cm (range 0.6-23) in HRT respectively. Half of the patients had visceral metastases (48.4% vs 54.3%). Both cohorts had a median of 1 prior line of systemic treatment. More than half of the patients had concurrent systemic treatment continued (61.3% vs 56.8%). Rates of completion of RT were similar (96.8% vs 96.3%). More patients in the UHRT cohort had no further lines of systemic treatment (32.3% vs 9.9%).Median follow up time was at least 10 months (10.3 months vs 16.3 months), local control was similar at 12 months (both 60.1%), as shown in figure 1 (p value = 0.082).
≥ G3 Acute radiation dermatitis was lower in UHRT (6.3% vs 16.9%). Symptom control including pain, ulceration, bleeding and discharge of evaluable patients received UHRT at 12 weeks were comparable to those received HRT (Figure 2). Median change in tumor size at 12 weeks was higher in UHRT (-41.2% vs - 28.6%). Retreatment rates (13.3% vs 14.1%) and median time to retreatment (19.1 months vs 14.6 months) were similar. Median OS was not statistically significant (15.2 months, 95% CI 8.0-22.4, vs 20.9 months, 95% CI 9.5-32.3, p= 0.11).
Conclusion: Ultrahypofractionated palliative radiotherapy using 26Gy/5Fr is a safe and effective regimen for local control and symptom relief in inoperable or metastatic breast cancer. For selected patients with good performance status, may consider a more protracted HRT schedule for a more durable local control. References: 1. Brunt AM, Haviland JS, Wheatley DA, et al. Hypofractionated breast radiotherapy for 1 week
Made with FlippingBook - Share PDF online