Trends of axillary surgery in breast cancer patients with axillary lymph node metastasis: a comprehensive single-center retrospective study

Purpose: Based on the results of previous trials, de-escalation of axillary surgery after neoadjuvant chemotherapy (NAC) has increased in patients with axillary lymph node (ALN) metastasis at presentation. This study aimed to review the trends of axillary surgery by time period and molecular subtype in patients with ALN metastasis. Methods: We analyzed the rates of sentinel lymph node biopsy (SLNB) and ALN dissection (ALND) based on time period and subtype. The time period was divided into 3 subperiods to determine the rate of axillary surgery type over time (period 1, from 2009 to 2012; period 2, from 2013 to 2016; and period 3, from 2017 to July 2019). Results: From 2009 to July 2019, 2,525 breast cancer patients underwent surgery. Based on subtype, the ALND rate of hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2–) disease decreased by 13.0% from period 1 to period 3 (period 1, 99.4%; period 2, 97.5%; and period 3, 86.4%; P < 0.001). Conversely, the ALND rate in HR+/HER2+, HR–/HER2+, and triple-negative breast cancer (TNBC) significantly decreased by 43.7%, 48.8%, and 35.2% in period 1, period 2, and period 3, respectively (P < 0.001). In the patient group receiving NAC, HR+/HER2– had a significantly higher ALND rate (84.1%) than HR+/HER2+, HR–/HER2+, and TNBC (60.8%, 62.3%, and 70.7%, respectively; P < 0.001). Conclusion: The SLNB rate in patients with ALN metastasis has increased over time. However, the ALND rate in HR+/ HER2– was significantly higher than in other subtypes.