Abstract P5-22-15: Hormone receptor status is a predictive factor for axillary lymph node recurrence after sentinel lymph node biopsy

Abstract

Abstract Background Axillary staging is important for predicting prognosis, and for local control in early breast cancer. Sentinel lymph node biopsy (SLNB) is a widely accepted method to avoid unnecessary axillary lymph node dissection (ALND). Since the ACOSOG Z0011 trial was published, we have refrained from ALND for selected patients with positive SLNB results. However, some cases have shown regional lymph node recurrences after SLNB without axillary dissection. The purpose of this study is to identify risk factors for recurrences, to ensure a safe axillary surgery. Methods A retrospective review of 1011 patientswho underwent SLNB without ALND between June 2004 and March 2017 was performed. Since October 2012, we have not performed ALND in patients (a) with 1 or 2 positive sentinel lymph nodes (SLNs), (b) with positive SLNs that are unmatted or not gross extra nodal extension, (C) in whom clinical tumor size is <5 cm, and (d) who receive adjuvant endocrine therapy or chemotherapy and radiotherapy. Cases of mastectomy, lumpectomy with a positive margin and additional resection or boost radiotherapy, and bilateral cancer were included. SLNs were identified using technetium sulfur colloid and indigo carmine blue dye, and were bisected in parallel to the long axis of the nodes. The sections were stained with hematoxylin and eosin. Adjuvant systemic and/or radiation treatment was delivered as per the National Comprehensive Cancer Network and the Japanese Breast Cancer Society clinical practice guidelines and was based on the patients' pathological and clinical traits. Results Of the 1011 patients, 969 had negative and 42 had positive SLNs. The median age of patients was 59 years (range 21-88). The median invasive breast tumor size was 15 mm (range 0.05-85), with 1.9% tumors being pathological T3 lesions; 127 patients (12.3%) developed lymphatic vessel invasion. SLNs identification rate was 99.4%. The median number of SLNs removed per patient was 2 (range 1-7). After follow-up of a median 78.5 months, 10 patients (1.0%) had an axillary recurrence and all of them had negative SLN metastasis. The median time to axillary recurrence was 26 months (range 9-94). The hormone receptor (HR) status was significantly related to axillary recurrence (p=0.008). While triple negativity had a tendency to relate (p=0.06), human epidermal growth factor receptor 2 (HER2) status did not correlate with axillary recurrence (p=0.13). Tumor subtypes and axillary recurrence SLNB without ALND (n=1011)Axillary recurrenceP valueHR positive72650.009HR negative1615 HER2 positive12130.13HER2 negative7667 Triple Negative10030.06Not Triple Negative7877 DCIS1240 DCIS: Ductal carcinoma in situ Conclusions As reported previously, the axillary recurrence rate after SLNB was low. Our results show that HR negativity was a significant factor for axillary recurrence. Although the ACOSOG Z0011 trial criteria focused on ALNB positive cases, they do not mention the tumor subtypes. Our findings show that HR negative patients without ALND have to follow up carefully. Citation Format: Sekine C, Nakano S, Mibu A, Otsuka M, Oinuma T. Hormone receptor status is a predictive factor for axillary lymph node recurrence after sentinel lymph node biopsy [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-22-15.