Dummy Run of Quality Assurance Program in a Phase 3 Randomized Trial Investigating the Role of Internal Mammary Lymph Node Irradiation in Breast Cancer Patients: Korean Radiation Oncology Group 08-06 Study
- Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul (Korea, Republic of)
- Department of Radiation Oncology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul (Korea, Republic of)
- Department of Radiation Oncology, Proton Therapy Center, Research Institute and Hospital, National Cancer Center, Goyang (Korea, Republic of)
- Department of Radiation Oncology, Asan Medical Center, University of Ulsan, College of Medicine, Seoul (Korea, Republic of)
- Department of Radiation Oncology, Chonnam National University Medical School, Gwangju (Korea, Republic of)
- Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)
- Department of Radiation Oncology, Dong-A University Hospital, Dong-A University School of Medicine, Busan (Korea, Republic of)
- Department of Radiation Oncology, Pusan National University Hospital, Pusan National University School of Medicine, Busan (Korea, Republic of)
- Department of Radiation Oncology, Gachon University Gil Medical Center, Incheon (Korea, Republic of)
- Department of Radiation Oncology, Ewha Womans University Mokdong Hospital, Seoul (Korea, Republic of)
- Department of Radiation Oncology, Dongsan Medical Center, Keimyung University School of Medicine, Daegu (Korea, Republic of)
- Department of Radiation Oncology, Bundang CHA Hospital, School of Medicine, CHA University, Seongnam (Korea, Republic of)
Purpose: The Korean Radiation Oncology Group (KROG) 08-06 study protocol allowed radiation therapy (RT) technique to include or exclude breast cancer patients from receiving radiation therapy to the internal mammary lymph node (IMN). The purpose of this study was to assess dosimetric differences between the 2 groups and potential influence on clinical outcome by a dummy run procedure. Methods and Materials: All participating institutions were asked to produce RT plans without irradiation (Arm 1) and with irradiation to the IMN (Arm 2) for 1 breast-conservation treatment case (breast-conserving surgery [BCS]) and 1 mastectomy case (modified radical mastectomy [MRM]) whose computed tomography images were provided. We assessed interinstitutional variations in IMN delineation and evaluated the dose-volume histograms of the IMN and normal organs. A reference IMN was delineated by an expert panel group based on the study guidelines. Also, we analyzed the potential influence of actual dose variation observed in this study on patient survival. Results: Although physicians intended to exclude the IMN within the RT field, the data showed almost 59.0% of the prescribed dose was delivered to the IMN in Arm 1. However, the mean doses covering the IMN in Arm 1 and Arm 2 were significantly different for both cases (P<.001). Due to the probability of overdose in Arm 1, the estimated gain in 7-year disease-free survival rate would be reduced from 10% to 7.9% for BCS cases and 7.1% for MRM cases. The radiation doses to the ipsilateral lung, heart, and coronary artery were lower in Arm 1 than in Arm 2. Conclusions: Although this dummy run study indicated that a substantial dose was delivered to the IMN, even in the nonirradiation group, the dose differences between the 2 groups were statistically significant. However, this dosimetric profile should be studied further with actual patient samples and be taken into consideration when analyzing clinical outcomes according to IMN irradiation.
- OSTI ID:
- 22458610
- Journal Information:
- International Journal of Radiation Oncology, Biology and Physics, Vol. 91, Issue 2; Other Information: Copyright (c) 2015 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0360-3016
- Country of Publication:
- United States
- Language:
- English
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