Trends in Axillary Surgery for Treating Ductal Carcinoma In Situ : A Korean Population-based Study

Ductal carcinoma (DCIS) is common in South Korea. We evaluated the patterns of axillary surgery among patients with DCIS to highlight the need for compliance with the updated national guidelines. We also evaluated whether sentinel lymph node biopsy (SLNB) was performed in accordance with the national guidelines. The Korean Health Insurance Review and Assessment Service-National Inpatient Sample database was searched for patients with DCIS (2009-2015) to identify axillary surgery patterns by breast surgery type, year of diagnosis, age at diagnosis, and the location and volume of surgeries for DCIS at the hospital. The rates of SLNB and axillary dissection were compared using descriptive statistics and univariate analyses. Analyses were also conducted using the chi-squared test and multiple logistic regression analysis. We identified 16,315 Korean women who underwent surgery for DCIS, including 11,292 cases of SLNB (69.2%) and 131 cases of axillary lymph node dissection (0.8%). Breast-conserving surgery (BCS) was performed in 10,323 patients (63.3%) with an SLNB rate of 56.0%, while total mastectomy (TM) was performed in 5,992 patients (36.7%), with an SLNB rate of 92.0%. During 2009-2015, the SLNB rate during TM increased from 88.23% to 92.80%. SLNB was influenced by hospital region and surgical volume, and hospitals performing low volumes of surgeries were significantly more likely to perform SLNB regardless of the surgery type (odds ratio, 1.372; 95% confidence interval, 1.265-1.488). Although the Korean guidelines recommend SLNB for all TM procedures and select BCS procedures for DCIS, relatively high rates of SLNB were performed for BCS, and there was inter-hospital variability in performing SLNB. Improved compliance with the guidelines by the surgeons is critical for Korean patients with DCIS.