ESTRO 2022 - Abstract Book

S1032

Abstract book

ESTRO 2022

Radiation Oncology, Hwasun, Korea Republic of; 14 Dongnam Institute of Radiological and Medical Sciences, Department of Radiation Oncology, Busan, Korea Republic of; 15 Pusan National University School of Medicine, Department of Radiation Oncology, Busan, Korea Republic of; 16 Korea University Medical College, Department of Radiation Oncology, Seoul, Korea Republic of; 17 Keimyung University School of Medicine, Department of Radiation Oncology, Daegu, Korea Republic of; 18 Yonsei University Wonju College of Medicine, Department of Radiation Oncology, Wonju, Korea Republic of; 19 Chosun University Medical School, Department of Radiation Oncology, Gwangju, Korea Republic of Purpose or Objective We aimed to investigate manifestations and patterns of care for patients with brain metastasis (BM) from breast cancer (BC) and compared their overall survival (OS) from 2005 through 2014 in Korea. Materials and Methods We retrospectively reviewed 600 BC patients with BM diagnosed between 2005 and 2014. The median follow-up duration was 12.5 months. We categorized the patients into three groups according to the year when BM was initially diagnosed [group I (2005–2008), 98 patients; group II (2009–2011), 200 patients; and group III (2012–2014), 302 patients]. Results Over time, the median age at BM diagnosis increased by 2.2 years (group I, 49.0 years; group II, 48.3 years; and group III, 51.2 years; p=0.008). The percentage of patients with extracranial metastasis was 73.5%, 83.5%, and 86.4% for group I, II, and III, respectively (p=0.011). The time interval between BC and BM was prolonged in patients with stage III primary BC (median, 2.4 to 3 years, p=0.029). As an initial brain-directed treatment, whole-brain radiotherapy alone decreased from 80.0% in 2005 to 41.1% in 2014. Meanwhile, stereotactic radiosurgery or fractionated stereotactic radiotherapy alone increased from 13.3% to 34.7% during the same period (p = 0.005). The median OS for group I, II, and III was 15.6, 17.9, and 15.0 months, respectively, with no statistical significance. Conclusion The manifestations of BM from BC and the pattern of care have changed from 2005 to 2014 in Korea. However, the OS has remained relatively unchanged over the 10 years. Purpose or Objective We aimed to estimate the cumulative incidence of lymphedema in patients with breast cancer who received postoperative radiotherapy (RT). We compared hypofractionated and conventional RT for lymphedema development and identified novel prognostic factors affecting lymphedema in these patients. Materials and Methods A total of 590 patients with ductal carcinoma in situ or invasive carcinoma of the unilateral breast were retrospectively reviewed. The median follow-up duration after RT was 5.4 years (range, 1.0–6.3 years). All patients underwent breast surgery and postoperative RT with or without systemic treatment in 2015. Hypofractionated RT with a median fraction size of 2.7 Gy was administered to 405 (68.6%) patients. Results A total of 109 (18.5%) patients experienced lymphedema during follow-up. The cumulative incidence of lymphedema at 1, 2, 3, and 5 years was 10.5%, 14.8%, 17.0%, and 18.2%, respectively. There was no difference in the incidence of lymphedema between patients with hypofractionated or conventional RT (3-year cumulative incidence, 18.3% vs. 14.0%, p=0.220). Multivariate analysis showed that high body mass index (hazard ratio [HR] 1.066, 95% confidence interval [CI] 1.020–1.115, p=0.005), left-sided breast cancer (HR 1.498, 95% CI 1.007–2.229, p=0.046), a large number of dissected lymph nodes (HR 1.041, 95% CI 1.008–1.075, p=0.015), and taxane-based chemotherapy ( neoadjuvant, HR 3.792, 95% CI 1.590–9.048, p=0.003; and adjuvant, HR 2.572, 95% CI 1.097–6.033, p=0.030) were significantly associated with increased lymphedema risks. For patients not receiving adjuvant chemotherapy, a prolonged interval between surgery and RT decreased the likelihood of lymphedema (HR 0.579, 95% CI 0.355–0.925, p=0.023). Conclusion We did not find any relationship between lymphedema and the scheme of RT. However, a shorter interval from surgery to RT when adjuvant chemotherapy was not performed may affect lymphedema development. Although further validation is required, left-sided breast cancer was associated with a higher risk of lymphedema than right-sided breast cancer in this study. PO-1220 Hypofractionated vs. conventional postoperative radiotherapy on breast cancer-related lymphedema J.S. Kim 1 , J.H. Kim 1 , J.H. Chang 1 , D.W. Kim 1 , K.H. Shin 1 1 Seoul National University College of Medicine, Department of Radiation Oncology, Seoul, Korea Republic of

PO-1221 Body mass index in breast cancer patients treated with intra-operative electronic brachytherapy

B. Schwartzberg 1 , A.M.N. Syed 2 , M. Farha 3 , C. Hodge 4 , C. Wengler 5

1 Schwartzberg Center for Minimally Invasive Breast Surgery, Surgery, Santa Rosa, California, USA; 2 MemorialCare Health System, Radiation Oncology, Long Beach, California, USA; 3 MedStar Good Samaritan Hospital, Surgery, Baltimore,