Abstract P6-02-16: The efficacy of preoperative pathological features to improve diagnosis accuracy in lymph node metastasis by axillary ultrasound

Abstract

Purpose Recently a sentinel lymph node biopsy has been a part of standard surgical procedure instead of an axillary dissection with a mastectomy for breast cancers. It is necessary to make an accurate diagnosis of lymph node metastasis for deciding surgical procedure either a sentinel lymph node biopsy or an axillary dissection. Preoperative ultrasound is one of widely used tools to make a diagnosis of sentinel lymph node. This study presents results regarding preoperative pathological features to improve diagnosis accuracy of sentinel lymph node by preoperative axillary ultrasound. Materials and methods One doctor performed preoperative ultrasound. He used HITACHI HI VISION Ascendus. Axillary lymph node metastasis was suspected when these findings were observed such as partial thickening of lymph node cortex, loss of lymph nodes9 hilum, circular swelling shape change and difference compared to a contralateral axillary lymph node. When we suspected axillary lymph node metastasis, we performed fine needle aspiration cytology except other findings such as CT, MRI or physical appearance showed obvious axillary lymph node metastasis. Preoperative core needle biopsies were performed to determine pathologic types and hormone characters. Clinical cases such that ductal carcinoma in situ, lobular carcinoma and ones with primary systemic treatment (neoadjuvant therapy) were excluded from statistical analysis. Results During a study period between April 2015 and December 2017, altogether 662 patients were participated in this study. 304 cases were analyzed by statistical analysis. 268 cases were diagnosed as negative and 36 case as positive in axillary lymph node metastasis by preoperative ultrasound. In the 268 cases 225 cases were diagnosed as negative by sentinel lymph node biopsy during operations (84.0%) but 43 cases were diagnosed as positive (16.0%). 23% cases included less than 20mm micro metastasis (10/43). To investigate correlation between false negative ratio of axillary lymph node metastasis diagnosed by an ultrasound and preoperative pathological features such as hormone receptor, HER2, Ki-67, nuclear grade and subtypes (Luminal, Her2 and triple negative). The false negative ratio was 17.0% vs 11.1% in hormone receptor (positive vs negative, p = 0.434), 14.5% vs 16.0% in HER2 (positive vs negative, p = 0.887), 15.4% vs 19.1% in Ki-67 ( 0.05). Conclusion There were no statistical significant difference between the axillary lymph node metastasis diagnosed by an ultrasound and the preoperative pathological features. However cases categorized in Luminal B by preoperative pathology had relatively high false negative ratio of axillary lymph node metastasis diagnosed by an ultrasound. It is necessary to investigate a way to improve diagnosis accuracy of sentinel lymph node by a preoperative axillary ultrasound. Citation Format: Koike R, Fujita T, Sata N, Shiozawa M, Miyazaki C, Sakuragi M, Shiba S, Tanaka Y. The efficacy of preoperative pathological features to improve diagnosis accuracy in lymph node metastasis by axillary ultrasound [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-02-16.