LAUSR

Introduction: Ultrasound-guided fine needle aspiration cytology (US-FNAC) in breast cancer has been suggested as a cost-effective exam and of quick performance to detect axillary involvement. However, the efficacy of ultrasound-guided biopsy can vary in distinct centers because the accuracy of ultrasound examination is operator- dependent. Objective: To report the accuracy of US-FNAC to detect axillary involvement in breast cancer and to compare with other methods of axilla assessment: Axillary palpation (AP) and isolated axillary ultrasound (A-US) in our institution. Method: An accuracy study was carried out, using data of breast cancer patients assisted at a mastology service, between 2013 and 2017 in Recife, Brazil. Sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) of the AP, the A-US and US-FNAC. A histopathological result (sentinel lymph node and/or axillary dissection) was adopted as a gold standard. This study was approved by the Research Ethics Committee of the institution. Results: 206 tumors were analyzed. The US-FNAC was performed in 142 (49.5%) cases and positive for malignancy in 74 (25.6%). AP presented the lowest sensitivity (58.3%, 95%CI 49-67.3), however, with an accuracy of 69.9%, better than the A-US, whose accuracy was 68%. The US-FNAC showed high specificity (100%) with PPV of 100%, but with low NPV (53.6%). The best NPV was AP (59.7%), followed by A-US (59.1%). The US-FNAC accuracy was 83.5%. Table - Sensitivity, specificity, accuracy and predictive values of the AP, A-US and US-FNAC with a gold standard (histopathology) in the diagnosis of axillary involvement in breast cancer in women assisted at the mastology service at IMIP, Recife, Brazil, 2013- 2017. AP = axillary palpation, A-US=axillary ultrasound, US-FNAC= ultrasound-guided fine needle aspiration cytology, PPV=positive predictive value, NPV=negative predictive value. Conclusion: The good accuracy associated to the high specificity and the PPV of the US-FNAC suggests US-FNAC to be a good exam in the diagnosis of axillary involvement in breast cancer and an ally to better define therapeutic management. Keywords: Breast Neoplasms; Biopsy, Fine-Needle; Neoadjuvant Therapy; Sentinel Lymph Node; Ultrasonography, Mammary. Citation Format: Maria Carolina Gouveia, Candice Lima Santos, Isabel Cristina Pereira, Jose Natal Figueiroa, Ariani Impieri Souza. Accuracy of ultrasound-guided fine needle aspiration citology (US-FNAC) to detect axillary involvement in breast cancer [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 P4-02-15.