ESTRO 2024 - Abstract Book

S530

Clinical - Breast

ESTRO 2024

Conclusion:

Limited RNI, excluding AXL1 from the radiation field, demonstrated axillary recurrence rates comparable to those of extensive RNI in patients with breast cancer. The study suggests that extensive RNI may not provide additional therapeutic benefits, while limited RNI appears to be a valid option for regional control.

Keywords: breast cancer, axilla, lymphatic metastasis

1018

Poster Discussion

Quality assurance in trial of hypofractionated reginal nodal irradiation in breast cancer (HARVEST)

Jia-Yi Chen 1 , Fei-Fei Xu 1 , Gang Cai 1 , Lu Cao 1 , Wei-Xiang Qi 1 , Xiao-Bo Huang 2 , Qi-Wei Zhu 3 , Yu-tian Zhao 4 , Qing Lin 5 , Ming Ye 6 , Yuan Yao 7 , Bo Yu 8 1 Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Department of Radiation Oncology, Shanghai, China. 2 Sun Yat-sen University Cancer Center, Department of Radiation Oncology, Guangzhou, China. 3 Affiliated Tumor Hospital of Nantong University, Department of Radiation Oncology, Nantong, China. 4 Affiliated Hospital of Jiangnan University, Department of Radiation Oncology, Jiangsu, China. 5 Shanghai Tenth People‘s Hospital, Department of Radiation Oncology, Shanghai, China. 6 Renji Hospital, Shanghai Jiaotong University School of Medicine, Department of Radiation Oncology, Shanghai, China. 7 Shanghai Ninth People‘s Hospital, Department of Radiation Oncology, Shanghai, China. 8 Affiliated Jiangyin Hospital of Nantong University, Department of Radiation Oncology, Jiangyin, China

Purpose/Objective:

The HARVEST trial (NCT03829553) is a phase III, multicenter, randomized clinical trial to explore efficacy and safety of hypofractionated irradiation (HFI) involving regional nodal irradiation (RNI, including internal mammary nodes, IMN) in N+ breast cancer patients treated with mastectomy or breast conserving surgery (BCS). Current study aims to analyze the dosimetric quality assurance so as to evaluate the compliance to the trial protocol.

Material/Methods:

Eligible patients were randomly assigned (1:1) to receive conventional fractionated irradiation (CFI: 50Gy/25Fx) or HFI (40.05Gy/15Fx), which is delivered to ipsilateral chest wall or whole breast (CW/WB) with tumor bed boost (HFI: 10.68Gy/4Fx; CFI: 10Gy/5Fx) and comprehensive RNI (supra/infraclavicular nodes and IMN in each patient, lower axilla if indicated) by using IMRT technique. The plan quality was evaluated based on dose distribution, dose volume histogram (DVH) and field parameters. The target coverage, including planning target volume of CW/WB (PTV1) and