What happened to clinically node positive breast cancer patients who showed conversion into pN0 after neoadjuvant chemotherapy?: Single center for 10 years

Objective: This study aimed to evaluate the outcomes between sentinel lymph node biopsy (SLNB) and axillar lymph node dissection (ALND) on recurrence and survival in clinically node positive breast cancer patients who showed conversion into pN0 after neoadjuvant chemotherapy (NAC) from 10 years cohort in single center. Materials \u0026 Method: This study enrolled total 225 patients, from January 2006 to December 2015 who underwent breast cancer surgery and axillar lymph node approach in clinically axillar lymph node metastasis with conversion into node negative after neoadjuvant chemotherapy. One hundred patients had only SLNB and 125 patients had ALND finally. Results: The median follow-up time was 58 months (range, 12-147 months) in only SLNB group and 103 months (range 9-174 months) in ALND group and the median number of retrieved SLNs was 2 (range, 1-6) and 11 (2-31). The 5 years overall survival rate of SLNB and ALND group is 94%, 95.7% (P=0.786), disease free survival rate 91.9%, 91.6%, (p=0.753) which was not statistically significant. Three patients (3%) and 6 patients (4.8%) showed loco-regional recurrence respectively. All they showed ipsilateral axillary lymph node recurrence. Seven patients (7%) and 6 patients (4.8%) in SLNB group and ALND group showed distant metastasis. However, there were more complications in the ALND group than in the SLNB group. Among them, ALND group showed the higher rate of shoulder stiffness than SLNB group (7% vs 10.4%, p=0.384, respectively). Especially, the incidence of lymphedema was 6 times higher in ALND group. (4 patients (4%) vs 29 patients (23.2%), p=0.271) Conclusion: We found the SLNB only group did not increase the recurrence or metastatic rate from the patients, but reduced the incidence of complications such as lymphedema from the 10 years single center cohort. Therefore, we suggest SLNB can be considered as a reliable as an alternative to ALND when the complete response is achieved by re-staging with imaging study after neoadjuvant chemotherapy. Keyword: neoadjuvant chemotherapy, sentinel lymph node biopsy, axillar lymph node dissection Citation Format: Joo Hwa Kwak, Heein Jo, Eun-Gyeong Lee, Eun Jin Song, Jai Hong Han, So-Youn Jung, Han-Sung Kang, Eun Sook Lee, Seeyoun Lee. What happened to clinically node positive breast cancer patients who showed conversion into pN0 after neoadjuvant chemotherapy?: Single center for 10 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 P4-02-08.