Jiwoong Jung1, Wonshik Han2, Eun Sook Lee3, So-Youn Jung3, Jai Hong Han3, Dong-Young Noh2, Yumi Kim2, Hee Jun Choi4, Jeong Eon Lee4, Seok Jin Nam4, Jong Won Lee5, Hee Jeong Kim5, Eunhae Um6, Joo Heung Kim7, Seho Park8, Young Up Cho9. 1. Department of Surgery, Seoul Medical Center, Seoul, Korea. 2. Department of Surgery, Seoul National University College of Medicine, Seoul, Korea. 3. Center for Breast Cancer, Research Institute and Hospital, National Cancer Center, Goyang, Korea. 4. Division of Breast Surgery, Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea. 5. Division of Breast Surgery, Department of Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea. 6. Department of Surgery, Ilsan Paik Hospital, University of Inje, Goyang, Korea. 7. Department of Surgery, National Health Insurance Service Ilsan Hospital, Goyang, Korea. 8. Department of Surgery, Severance Hospital, Yonsei University College of Medicine, 50-1, Yonsei-Ro, Seodaemun-Gu, Seoul, 03722, Republic of Korea. 9. Department of Surgery, Severance Hospital, Yonsei University College of Medicine, 50-1, Yonsei-Ro, Seodaemun-Gu, Seoul, 03722, Republic of Korea. youngup@yuhs.ac.
Abstract
PURPOSE: The Z0011 trial demonstrated that axillary dissection (ALND) could be omitted during breast-conserving therapy for cT1-2N0 breast cancers with 1-2 metastatic SLNs. However, that result has not been validated in a larger cohort and the significance of the small number of SLNs remains unclear. This study aimed to validate the Z0011 results within an Asian Z0011-eligible cohort and determine whether the number of sentinel lymph nodes (SLNs) influenced the Z0011-based outcomes. METHODS: Data from Asian patients who fulfilled the Z0011 criteria were collected from five hospitals. Disease recurrence (DR) was compared between patients who underwent ALND or SLN dissection (SLND) alone. Propensity-score matching was performed to reduce the effects of potential selection biases. RESULTS: During 2010-2016, 1750 Asian patients had 1-2 SLN metastases and fulfilled the Z0011 criteria. These patients included 707 cases treated using SLND alone (40%) and 967 patients with ≤ 2 SLNs (55%). Ninety-five patients (5.4%) experienced DR at a median interval of 50 months, although the rates of DR were similar in the ALND and SLND groups. The adjusted hazard ratios for DR after ALND omission were 0.95 (95% CI 0.55-1.64) among the entire cohort and 0.83 (95% CI 0.34-2.03) among patients with ≤ 2 SLNs. CONCLUSIONS: In this Asian Z0011-eligible cohort, ALND omission did not increase risk of DR, even among patients with ≤ 2 SLNs. Therefore, the Z0011 strategy might be safely applied in Asia, and a small number of SLNs did not significantly influence this strategy.
PURPOSE: The Z0011 trial demonstrated that axillary dissection (ALND) could be omitted during breast-conserving therapy for cT1-2N0 breast cancers with 1-2 metastatic SLNs. However, that result has not been validated in a larger cohort and the significance of the small number of SLNs remains unclear. This study aimed to validate the Z0011 results within an Asian Z0011-eligible cohort and determine whether the number of sentinel lymph nodes (SLNs) influenced the Z0011-based outcomes. METHODS: Data from Asian patients who fulfilled the Z0011 criteria were collected from five hospitals. Disease recurrence (DR) was compared between patients who underwent ALND or SLN dissection (SLND) alone. Propensity-score matching was performed to reduce the effects of potential selection biases. RESULTS: During 2010-2016, 1750 Asian patients had 1-2 SLN metastases and fulfilled the Z0011 criteria. These patients included 707 cases treated using SLND alone (40%) and 967 patients with ≤ 2 SLNs (55%). Ninety-five patients (5.4%) experienced DR at a median interval of 50 months, although the rates of DR were similar in the ALND and SLND groups. The adjusted hazard ratios for DR after ALND omission were 0.95 (95% CI 0.55-1.64) among the entire cohort and 0.83 (95% CI 0.34-2.03) among patients with ≤ 2 SLNs. CONCLUSIONS: In this Asian Z0011-eligible cohort, ALND omission did not increase risk of DR, even among patients with ≤ 2 SLNs. Therefore, the Z0011 strategy might be safely applied in Asia, and a small number of SLNs did not significantly influence this strategy.