Abstract PS1-53: Does the axilla surgical management for limited sentinel lymph nodes involvement vary between total mastectomy and breast-conserving surgery
Authors: Gao Weiqi , Chen Xiaosong , Shen Kunwei 
Published: February 2021

Abstract
Purpose: The ACOSOG Z0011 study demonstrated that axillary lymph node dissection (ALND) can be safely omitted in patients with one to two positive sentinel lymph node (SLN) who underwent breast-conserving surgery (BCS) with planned whole-breast irradiation. This study aimed to analysis the surgical management in patients with one to two positive SLNs, and further evaluate the rates of non-sentinel lymph node (non-SLN) metastasis between patients receiving BCS or total mastectomy (TM). Methods: We performed a retrospective analysis of patients with early breast carcinoma from the Shanghai Jiao Tong University-Breast Cancer Database (SJTU-BCDB) between 2011 to 2018. The inclusion criteria were (1) cT1-2N0M0 invasive breast cancer, (2) aged ≥18 years at diagnosis, (3) received surgical treatment for the primary tumor and the axilla, (4) had one to two positive SLNs, (5) no history of previous or concurrent malignant disease, and (6) no neoadjuvant therapy. Patients were classified into the BCS and TM groups. Time trends of ALND rates were analyzed with Chi-square tests. And the rates of non-SLN metastasis between BCS and TM groups were also analyzed with Chi-square tests. Multivariable logistic regression was used to determine factors influencing the completion of ALND and non-SLN metastasis. And Kaplan-Meier estimator and log-rank tests were used to analysis the recurrence-free survival (RFS) between SLNB alone and SLNB+ALND arms. Results: Of the 891 patients enrolled, 586 (65.8%) received TM and 305 (34.2%) received BCS. Between 2011 and 2018, the completion of ALND for 1-2 positive SLN decreased from 100% to 72.7% (P &lt;0.001). And the rate of ALND was significantly higher in the TM group compared with the BCS group (n = 541, 92.3% vs n = 195, 63.9%; P &lt;0.001).Earlier year of diagnosis (P &lt;0.001), primary mastectomy (P &lt;0.001), SLN positive-total ratio &gt;50% (P =0.001), and SLN macro-metastasis (P &lt;0.001) were all independently associated with a higher probability of completing ALND. Among the 736 patients undergone ALND, the rates of non-SLN metastasis were significantly higher in the TM group, compared to the BCS groups (TM: n = 170, 31.4% vs BCS: n = 46, 23.6%; P =0.044). The multivariable regression analysis indicated that non-SLN metastasis was significantly associated with SLN positive-total ratio &gt;50% (OR=3.43, 95%CI 2.28-5.17; P &lt;0.001), Her-2 positive disease (OR=1.63, 95%CI 1.09-2.46; P =0.019), and pT2-3 disease (OR=1.46, 95%CI 1.01-2.09; P =0.042). However, surgery of the breast was not independently associated with the rate of non-SLN metastasis (P =0.090). After a median follow-up time of 31.9 months (range, 1.0-96.5 months), there were no significant difference in RFS between the SLNB alone and SLNB+ALND arms, regardless of the surgery of the breast (TM group: Log-rank P = 0.910; BCS group: Log-rank P =0.840). Conclusion: There is an increasing trend toward omitting ALND in patients with one to two positive SLNs. Compared with the patients undergone BCS, the rate of non-SLN metastasis was significantly higher in patients undergone TM. However, the omission of ALND had limited influence on disease outcome among those patients received TM.
Citation Format: Weiqi Gao, Xiaosong Chen, Kunwei Shen. Does the axilla surgical management for limited sentinel lymph nodes involvement vary between total mastectomy and breast-conserving surgery [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS1-53.