Won Kyung Cho1, Won Park2, Doo Ho Choi1, Yong Bae Kim3, Chang-Ok Suh3, Kyung Hwan Shin4, Eui Kyu Chie5, Jin Ho Kim6, Seung Do Ahn7, Su Ssan Kim7, Kyubo Kim8, Jin Hee Kim9, Sung Ja Ahn10, Sun Young Lee11, Jeongshim Lee12, Sang-Won Kim13, Jeanny Kwon14, Ki Jung Ahn15, Hyun Soo Shin16, Hyung Sik Lee17, Nam Kwon Lee18. 1. Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea. 2. Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea. Electronic address: wonro.park@samsung.com. 3. Department of Radiation Oncology, Yonsei University College of Medicine, Seoul, Republic of Korea. 4. Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Republic of Korea; Proton Therapy Center, Research Institute and Hospital, National Cancer Center, Republic of Korea. 5. Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Republic of Korea. 6. Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Republic of Korea. Electronic address: Jinho.kim.md@gmail.com. 7. Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea. 8. Department of Radiation Oncology, Ewha Womans University School of Medicine, Seoul, Republic of Korea. 9. Department of Radiation Oncology, Dongsan Medical Center, Keimyung University School of Medicine, Daegu, Republic of Korea. 10. Department of Radiation Oncology, Chonnam National University Medical School, Gwangju, Republic of Korea. 11. Department of Radiation Oncology, Chonbuk National University Medical School, Jeonju, Republic of Korea. 12. Department of Radiation Oncology, Inha University Hospital, Incheon, Republic of Korea. 13. Department of Radiation Oncology, Ajou University School of Medicine, Suwon, Republic of Korea; Department of Radiation Oncology, Konyang University College of Medicine, Daejeon, Republic of Korea. 14. Department of Radiation Oncology, Chungnam National University College of Medicine, Daejeon, Republic of Korea. 15. Department of Radiation Oncology, Inje University Busan Paik Hospital, Busan, Republic of Korea. 16. Department of Radiation Oncology, Bundang CHA Hospital, Seoul, Republic of Korea. 17. Department of Radiation Oncology, Dong-A University Hospital, Busan, Republic of Korea. 18. Department of Radiation Oncology, Korea Medical Center, Seoul, Republic of Korea.
Abstract
PURPOSE: This multi-institutional study intended to investigate the effect of tumor bed boost in patients who achieved pathologic complete response (ypCR) following neoadjuvant chemotherapy (NAC) and breast-conserving therapy (BCT). MATERIALS AND METHODS: We identified 180 patients who initially had lymph node (LN) metastasis and achieved ypCR (ypT0/isN0) following NAC and BCT from the 13 institutions of the Korean Radiation Oncology Group (KROG) 16-16 and KROG 12-05. The effect of tumor bed boost on loco-regional control (LRC), disease-free survival (DFS), and overall survival (OS) rates was analyzed. RESULTS: In all patients, five-year LRC, DFS and OS rates were 97.5%, 95.4%, and 99.4%, respectively. Tumor bed boost was performed in 158 (87.8%) patients. Advanced N-stage (cN2-3, p = 0.036), close resection margin (p < 0.001), and sentinel lymph node biopsy (p = 0.040) were unfavorable factors for DFS. Tumor bed boost was not a significant factor for LRC, DFS, and OS. CONCLUSIONS: This study suggests the benefit of tumor bed boost might be minimal in ypCR patients following NAC and BCT. Larger prospective studies are needed to address this issue.
PURPOSE: This multi-institutional study intended to investigate the effect of tumor bed boost in patients who achieved pathologic complete response (ypCR) following neoadjuvant chemotherapy (NAC) and breast-conserving therapy (BCT). MATERIALS AND METHODS: We identified 180 patients who initially had lymph node (LN) metastasis and achieved ypCR (ypT0/isN0) following NAC and BCT from the 13 institutions of the Korean Radiation Oncology Group (KROG) 16-16 and KROG 12-05. The effect of tumor bed boost on loco-regional control (LRC), disease-free survival (DFS), and overall survival (OS) rates was analyzed. RESULTS: In all patients, five-year LRC, DFS and OS rates were 97.5%, 95.4%, and 99.4%, respectively. Tumor bed boost was performed in 158 (87.8%) patients. Advanced N-stage (cN2-3, p = 0.036), close resection margin (p < 0.001), and sentinel lymph node biopsy (p = 0.040) were unfavorable factors for DFS. Tumor bed boost was not a significant factor for LRC, DFS, and OS. CONCLUSIONS: This study suggests the benefit of tumor bed boost might be minimal in ypCR patients following NAC and BCT. Larger prospective studies are needed to address this issue.