Abstract P4-03-03: Accuracy of stereotactic vacuum-assisted breast biopsy for investigating suspicious calcifications in 1,809 patients a public hospital in Brazil

Abstract

Abstract Background: The gold standard for breast biopsy procedures is currently an open excision of the suspected lesion. However, an excisional biopsy inevitably makes a scar. The cost and morbidity associated with this procedure has prompted many physicians to evaluate less invasive, alternative procedures. Stereotactic vacuum assisted breast biopsy (VASB) can provide a more accurate diagnosis and completely remove the lesion under real-time ultrasonic guidance. The advantage of complete lesion removal with VASB is to reduce or eliminate sampling error, to decrease the likelihood of a histological underestimation, to decrease imaging-histological discordance, to decrease the re-biopsy rate, and to diminish the likelihood of subsequent growth on follow-up, especially when stereotactic VASB is used to investigate microcalcifications. This method is expensive but cost effective when used to investigate microcalcifications classified as BI-RADS 4 and 5. Objectives: To evaluate the accuracy of VASB in the investigation of suspicious calcifications. Methods: We’ve performed a retrospective study from July, 2012 to June, 2019, in which 1,809 women with suspicious calcifications detected on mammography (BI-RADS 4 and 5) had VASB performed at Hospital Estadual Pérola Byington, a public Hospital in São Paulo, Brazil. The device used was Surus Pearl (Hologic, Malbolrough, Massachusetts, USA), with probe gauge 9. Fragments were obtained and sent to anatomopathological study; a metal clip was placed on the biopsy site. Four groups were analyzed, based on the biopsy results: benign, precursor lesions, Ductal Carcinoma In Situ (DCIS) and malignant. Most patients with positive or discordant cases underwent surgical treatment and the previous biopsy results were compared to surgery results. Results: patients median age was 55y (49-63). Pathology results on VASB and surgery were classified respectively as benign n=1,179 (65.1%), precursor lesions n=97 (5.4%), DCIS n=414 (22.9%) and malignant n=119 (6.6%). Benign and lesion precursor lesions results were clustered to form a new group (lower risk lesions) and so DCIS and malignant lesions (higher risk lesions). ROC curve and AUC were calculated to compare the results of lower and higher risk lesions groups according to VASB and surgery results (AUC=0,642). The X2 test was performed between the groups (p<0,05). The sensitivity of the method was 84.4 %, specificity was 96.1%, false negative rate was 4.5%, positive predictive value (PPV) was 89.8%, negative predictive value (NPV) was 93.8%. Conclusion: the VASB method has a good accuracy to distinguish lower and higher risk lesions groups comparing to the gold standard. It has high predictive value in both benign and malignant lesions, guiding therapeutic planning. Keywords: Calcifications; Vacuum-assisted stereotactic biopsy; Breast cancer; Diagnosis Citation Format: Andressa Amorim, Marcellus N. M. Ramos, André Mattar, Maria Isabela B. A. C. Sawada, Jorge Y. Shida, Luiz H. Gebrim. Accuracy of stereotactic vacuum-assisted breast biopsy for investigating suspicious calcifications in 1,809 patients a public hospital in Brazil [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 P4-03-03.