Analysis of non-sentinel lymph node status on 10-year overall survival among patients with breast cancer and sentinel lymph node metastasis.

e12584 Background: To investigate retrospectively the effect of non-sentinel lymph node status (non-SLN) on 10-year overall survival (OS) and non-SLN metastasis risk factors in patients with breast cancer and sentinel lymph node (SLN) metastasis. Methods: A large population (n = 15510) underwent SLN dissection in Cancer Hospital, Chinese Academy of Medical Sciences from 2011 to 2022. In total, 3033 (19.6%) cases had at least one SLN metastasis, which underwent axillary lymph node (ALN) dissection. The clinicopathological characteristics and their relationship with non-SLN status were analyzed. Among patients from 2011-2012(n = 132), the effect of non-SLN status on 10-year OS and disease-free survival (DFS) with SLN metastasis were also analyzed. Results: In 3033 patients with SLN metastasis, the mean age was (50.42±10.59) years. The average number of SLN metastasis in each patient was 1.75±1.21, the average number of SLN detected was 4.89±2.03 and the average number of ALN removed was 22.36±8.88. The number of SLN metastasis≥2 and positive lympho-vascular invasion were risk factors of non-SLN metastasis ( P< 0.05), but not the age, T stage and histological grade. In 132 patients from 2011-2012, a median follow-up of 9.1 years (interquartile range, 7.3-9.5 years), the non-SLN metastasis occurred in 60 cases (45.5%), DFS 70.8%, OS 85.9%; non-SLN non-metastasis occurred in 72 cases (54.5%), DFS 85.6%, OS 90.4%. There was no significant difference between two groups in DFS(χ² = 0.61, P = 0.43) and OS (χ² = 0.06, P = 0.81). Conclusions: The number of SLN metastasis≥2 and positive lympho-vascular invasion were risk factors of non-SLN metastasis. There were no significant differences between non-SLN metastasis group and non-metastasis group in DFS and OS.