Abstract P4-02-20: The clinical outcomes between sentinel lymph node biopsy and axillary lymph node dissection in Z0011 eligible cohort in single center for 15 years
Authors: Jo Heein , Kwak JooHwa , Lee Eun-Gyeong , Han Jai Hong , Jung So-Youn , Song Eun Jin , Kang Han-Sung , Lee EunSook , Lee Seeyoun 
Published: March 2020

Abstract
Background & Objective: The ACOSOG Z0011 trial announced in 2010, has been proved of successful local therapy with oncological safety by performing sentinel lymph node biopsy(SLBx) only, instead of traditional axillary lymph node dissection(ALND) for clinically node negative breast cancer patients. According to this result, paradigm of axilla surgery was changed and it was also reflected in updated NCCN guidelines. In 2017, A 10-year follow up of Z0011 was published. In terms of overall survival and disease free survival, there was no difference in the results between the SLBx only group and the ALND group.
We retrospectively reviewed all breast cancer patients to ascertain paradigm shift of breast cancer surgery after applying the Z0011 criteria for 15 years.
Materials & Method: All women who underwent breast conserving surgery at the National Cancer Center between January 1, 2000 and December 31, 2015 were enrolled and classified according to the Z0011 criteria. Finally, total 361 patients enrolled the study. The primary outcome of the study was to confirm the difference in mortality and recurrence rates among the SLBx only group, SLBx + sampling (picking up additional axilla lymph nodes) group and the ALND group, and the secondary outcome was to identify the complication among three groups.
Results: After the Z0011 guideline has adopted in our institute, the rate of ALND had rapidly decreased and lymph node sampling has replaced ALND. Of the 361 patients, 271 patients underwent formal ALND. 66 patients had SLBx only and 24 patients had further axillary node sampling in addition of SLBx. The number of retrieval total node was 13.02 in ALND group compared with 2.61 in SLBx only group and 5.71 in SLBx+sampling group with statistically significant(p=0.000). But there was no difference of the mean number of positive sentinel node among these groups.
Mean follow up period was 94.38 months(ALND 101.38months, SLBx only 77.61months, SLBx+sampling 61.54months, P=0.367). During follow-up, total 25 patients experienced disease recurrence. Twenty two patients were from ALND group and Three patients were from SLBx only group (p=0.787). Most common recurrence site was bone(4%), followed by Lung (3.7%), Liver(2.2%) and Brain(0.7%). Only six patients were dead by cause of breast cancer and all of them were from ALND group but there was no significant difference(p=0.574).
One hundred five patients (29.1%) experience the complication from operation. arm edema in the ALND group occurred about 40 times more than the SLBx only group (80 vs. 2) and 26 times more than the SLBx + sampling group(80 vs. 3), but there was no statistically significant(p=0.065).
Conclusion: From single center cohort for 15 years, we concluded that SLBx can be used safely in Z0011 eligible cohort without any increase of the risk of locoregional and distant recurrence. Also, we suggest omission of ALND can reduce some serious complication such as arm lymphedema.
Keyword: Z0011 criteria, Arm lymphedema, locoregional recurrence, sentinel lymph node biopsy, axillar lymph node dissection
Citation Format: Heein Jo, JooHwa Kwak, Eun-Gyeong Lee, Jai Hong Han, So-Youn Jung, Eun Jin Song, Han-Sung Kang, EunSook Lee, Seeyoun Lee. The clinical outcomes between sentinel lymph node biopsy and axillary lymph node dissection in Z0011 eligible cohort in single center for 15 years [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P4-02-20.