Impact of sentinel lymph node biopsy by ultrasound-guided core needle biopsy for patients with suspicious node positive breast cancer.

PURPOSE: The purpose of this study was to investigate the accuracy of preoperative diagnostic tools for axillary lymph nodes (LNs) staging of breast cancer.

MATERIALS AND METHODS: A total of 2464 consecutive patients with operable breast cancer were prospectively identified at our institution between April 2012 and March 2017. Patients with suspicious axillary LN of breast cancer were assessed using preoperative ultrasound(US) or computed tomography (CT), underwent fine-needle aspiration cytology (FNA) or core needle biopsy (CNB). The inclusion criteria for both FNA and CNB were a cortical thickness >3 mm or abnormal morphological characteristics. Patients with biopsy-proven metastasis underwent axillary lymph node dissection (ALND), and those with a negative FNA or CNB underwent sentinel lymph node biopsy (SNB). If the SNB was positive, ALND was performed. Diagnostic accuracy for SNB was calculated for both FNA and CNB. In addition, the patients in this study were divided into two groups as follows: the cN0-FNA group (suspicious LN but negative FNA) and cN0-CNB group (suspicious LN but negative CNB).

RESULTS: A number of patients with negative US/CT findings of LNs were 1406, with 744 undergoing FNA and 272 undergoing CNB for suspicious LNs. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were 65, 99, 99, 80, and 85% in FNA, and 87, 100, 100, 93 and 95% in CNB, respectively. SNB was performed in 172 (cN0-CNB group) of 272 CNB and 487 (cN0-FNA group) of 744 FNA patients. One hundred and seventy-two patients from the cN0-CNB group (Tis 6, T1 97, T2 66, T3 3 patients) treated with SNB were compared to 487 from the cN0-FNA group (Tis 21, T1 225, T2 233, T3 8 patients) in terms of number of LN metastasis. A number of patients with more than 3 positive SNB and positive LNs were 9 (5%) and 0 (0%) in cN0-CNB group, and 78 (16%) and 24 (5%) in cN0-FNA group, respectively. A number of patients who had complications such as haematoma and pain at the time of 7 to 14 days after CNB and FNA were 1 (0.5%) and 1 (0.5%) in cN0-CNB group, and were 0% and 0.2% in cN0-FNA group (p = 0.44), respectively.

CONCLUSIONS: The preoperative diagnosis of axillary LNs was influenced by the diagnostic tool used. CNB is a reliable method for the preoperative diagnosis of LN metastasis.