Stereotactic Vacuum-assisted Biopsy Research Articles

Abstract PO5-07-09: ACCURACY OF STEREOTACTIC VACCUM-ASSISTED BREAST BIOPSY FOR INVESTIGATING SUSPICIOUS CALCIFICATIONS IN 2,021 PATIENTS A PUBLIC HOSPITAL IN BRAZIL

Abstract Backgroud: the gold standard for breast biopsy procedures is currently an open excision of the suspected lesion. The cost and morbidity associated with this procedure has prompted many physicians to evaluate less invasive, alternative procedures. More recently, image-guided percutaneous core-needle biopsy has become a frequently used method for diagnosing palpable and non-palpable breast lesions. Although sensitivity rates for core-needle biopsy are high, it has the disadvantage of histological underestimation. Vacuum-assisted stereotactic biopsy (VASB) was developed to overcome some of these negative aspects of core-needle biopsy. Objectives: to evaluate the accuracy of vacuum-assisted stereotactic biopsy (VASB) in the investigation of non palpable suspicious calcifications. Methods: it was a retrospective study from July 2012 to December 2020, in which 2,021 women with suspicious calcifications detected on mammography (BI-RADS 4 and 5) had VASB performed at Hospital Estadual Pérola Byington, São Paulo, Brazil. 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 Invasive Ductal Carcinoma (ICD). Results: patients median age was 55y (49-63y). Pathology results on VASB were classified respectively as benign n=1,340 (66.3%), precursor lesions n=84 (4.1%), DCIS n=441 (21.8%) and ICD n=156 (7.7%). The 60 patients with results benign on VASB, because anatomopathological disagreement, surgery was performed, with the following results: benign n=30 (50%), ICD e DCIS n=21 (35%) e precursor lesions n=9 (15%). The sensitivity of the method was 91.7 %, specificity was 97.1%, false negative rate was 3%, positive predictive value was 92.4%, negative predictive value was 96.9%. 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, Andre Mattar, Marcelo Antonini, Reginaldo Coelho Lopes, Luciana Damous, Luiz Henrique Gebrim, Marina Diogenes, Marcellus Ramos. ACCURACY OF STEREOTACTIC VACCUM-ASSISTED BREAST BIOPSY FOR INVESTIGATING SUSPICIOUS CALCIFICATIONS IN 2,021 PATIENTS A PUBLIC HOSPITAL IN BRAZIL [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-07-09.

Assessing the malignancy of suspicious breast microcalcifications: the role of contrast enhanced mammography.

To assess the role of contrast-enhanced mammography (CEM) in predicting the malignancy of breast calcifications. We retrospectively evaluated patients with suspicious calcifications (BIRADS 4) who underwent CEM and stereotactic vacuum-assisted biopsy (VAB) at our institution. We assessed the sensitivity (SE), specificity (SP), positive predictive value (PPV) and negative predictive value (NPV) of CEM in predicting malignancy of microcalcifications with a 95% confidence interval; we performed an overall analysis and a subgroup analysis stratified into group A-low risk (BIRADS 4a) and group B-medium/high risk (BIRADS 4b-4c). We then evaluated the correlation between enhancement and tumour proliferation index (Ki-67) for all malignant lesions. Data from 182 patients with 184 lesions were collected. Overall the SE of CEM in predicting the malignancy of microcalcifications was 0.70, SP was 0.85, the PPV was 0.82, the NPV was 0.76 and AUC was 0.78. SE in group A was 0.89, SP was 0.89, PPV was 0.57, NPV was 0.98 and AUC was 0.75. SE in group B was 0.68, SP was 0.80, PPV was 0.87, NPV was 0.57 and AUC was 0.75. Among malignant microcalcifications that showed enhancement (N = 52), 61.5% had Ki-67 ≥ 20% and 38.5% had low Ki-67 values. Among the lesions that did not show enhancement (N = 22), 90.9% had Ki-67 < 20% and 9.1% showed high Ki-67 values 20%. The absence of enhancement can be used as an indicative parameter for the absence of disease in cases of low-suspicious microcalcifications, but not in intermediate-high suspicious ones for which biopsy remains mandatory and can be used to distinguish indolent lesions from more aggressive neoplasms, with consequent reduction of overdiagnosis and overtreatment.

Introduction of Stereotactic Vacuum-Assisted Breast Biopsy in Bulgaria

Summary Breast cancer is the most common cancer in women worldwide. The gold standard for biopsy is core needle biopsy. However, in certain cases, core needle biopsy cannot be applied, and the method of choice is vacuum-assisted biopsy. It is a minimally traumatic and precise method for diagnosing microcalcifications and small breast lesions. We aimed to present the initial experience with stereotactic vacuum-assisted biopsy in breast diseases at the Department of Surgical Oncology. We show indications and contraindications for this kind of biopsy and present our initial experience. From February 2020 to December 2022, 29 stereotactic vacuum-assisted biopsies were performed. Benign histology was found in 9 cases, malignant – in 15, and 5 cases were precancerous. Therefore, being an innovative, minimally invasive, and highly accurate method for diagnosing breast lesions with a good cosmetic effect, it allows early diagnosis of breast cancer, and, last but not least, the procedure can be curative for benign lesions.

Preoperative factors associated with underestimation of invasive breast cancer in stereotactic vacuum-assisted biopsy-diagnosed DCIS patients

Objective: To determine preoperative factors associated with underestimation of invasive breast cancer, where stereotactic vacuum-assisted biopsy (VAB) diagnosed as ductal carcinoma in situ (DCIS). Materials and Methods: Data from 95 patients diagnosed with DCIS by stereotactic VAB, including their clinical, radiological, and pathological findings between November 2010 and May 2021, were analyzed retrospectively. The clinical, radiological, and pathological features were analyzed. Results: The underestimation rate was 30.5 %. Three preoperative features were significantly associated with the underestimation of invasive breast cancer in multivariable analysis, including palpability (OR, 11.51; 95% CI: 1.817-72.897; P = 0.009), BI-RADS category (OR, 3.705; 95% CI: 1.214-11.303; P = 0.021), and visibility of a mammographically detected lesion at ultrasonography (OR, 7.115; 95% CI: 1.977-25.611; P = 0.003). The calcification morphology was statistically significant in an univariable analysis but not in a multivariable analysis. Conclusion: Preoperative variables significantly associated with underdiagnosis of invasive breast cancer, including palpability, BI-RADS category, and visibility of mammographically detected lesions at ultrasonography, could aid in assessing the risk of developing invasive breast cancer and conducting treatment selection.

Clinical performance of digital breast tomosynthesis–guided vacuum-assisted biopsy: a single-institution experience in Japan

BackgroundThe purpose of this study was to evaluate the clinical performance of Digital Breast Tomosynthesis guided vacuum-assisted biopsy (DBT-VAB) for microcalcifications in the breast.MethodsRetrospective review of 131 mammography-guided VABs at our institution were performed. All of the targets were calcification lesion suspicious for cancer. 45 consecutive stereotactic vacuum-assisted biopsies (ST-VABs) and 86 consecutive DBT-VABs were compared. Written informed consent was obtained. Tissue sampling methods and materials were the same with both systems. Student’s t-test was used to compare procedure time and the Fisher’s exact test was used to compare success rate, complications, and histopathologic findings for the 2 methods.ResultsThe tissue sampling success rate was 95.6% for ST-VAB (43/45) and 97.7% (84/86) for DBT-VAB. Time for positioning (10.6 ± 6.4 vs. 6.7 ± 5.3 min), time for biopsy (33.4 ± 13.1 vs. 22.5 ± 13.1 min), and overall procedure time (66.6 ± 16.6 min vs. 54.5 ± 13.0 min) were substantially shorter with DBT-VAB (P < 0.0001). There were no differences in the distribution of pathological findings between the 2 groups.ConclusionDepth information and stable visibility of the target provided by DBT images led to quick decisions about target coordinates and improved the clinical performance of microcalcification biopsies.

The Influence on Image Reconstruction Methods on Digital Breast Tomosynthesis Guided Vacuum-assisted Biopsy for Clustered Microcalcifications

In this study, we verified the targeting time and coordinates of stereotactic vacuum-assisted biopsy (STVAB) and digital breast tomosynthesis-guided vacuum-assisted biopsy (DBTVAB). We used 23 fabricated phantom samples that consisted of small round, amorphous, and pleomorphic clustered microcalcifications, and two types of image reconstruction methods: filtered back projection (FBP) and iterative super-resolution reconstruction (ISR). Regarding targeting time, DBTVAB tended to be shorter than STVAB in the two image reconstruction methods and the targeting time was significantly shorter for the amorphous and pleomorphic calcifications using DBTVAB with FBP compared to that using STVAB (p=0.022 for amorphous, p=0.041 for pleomorphic). The targeting time for small round calcifications was longer using DBTVAB with ISR compared to that using STVAB (p=0.013). For targeting coordinates, using DBTVAB with FBP showed a significant difference only for pleomorphic calcifications but using DBTVAB with ISR showed no significance. The findings of this study suggest that FBP is more suitable than ISR to be used as an image reconstruction method, and DBTVAB can shorten the targeting time compared to STVAB.

Unusual presentation of dermal microcalcifications on mammography images: A case report

Introduction. Calcifications and microcalcifications are mineral deposits in the breast tissue. Breast calcifications are a common mammographic finding, present on over 80% of images, and they are usually benign. Characteristics such as size, shape, number, distribution pattern, location, density, and other findings help determine the pathology. Dermal calcifications of the breast are superficial and benign calcifications that are usually found on the sebaceous glands of the skin. In some cases, calcifications can be the first marker of underlying cancer development. They may be associated with the presence of ductal carcinoma in situ or even invasive ductal carcinoma that has spread to the surrounding breast tissue. By correct identification of benign calcifications as such, unnecessary interventions and use of limited resources can be avoided. Case Report. A 66-year-old female patient presented for a regular mammography check-up. On the previous mammographic examination, she was categorized as bilateral breast imaging reporting and data system 1. The new mammography images showed numerous newly formed grouped microcalcifications at the junction of the lower quadrants of the right breast, and a stereotactic vacuum-assisted biopsy was indicated. During the biopsy attempt, the image guided biopsy program did not detect any calcifications in the parenchyma or in any projection and therefore it did not allow the biopsy procedure to continue after several attempts. Examination of the right breast skin revealed lesions treated by the patient for a few weeks; a repeat mammogram was performed and it was observed that the calcifications were of dermal origin. Conclusion. Dermal calcifications are mostly tiny, about the size of skin pores, single or clustered, and often have a calcified rim surrounding a lucent center. However, dermal calcifications deserve a special attention, because they sometimes lack a lucent center and simulate grouped intraparenchymal calcifications that require careful monitoring or biopsy.

Stereotactic vs open biopsy for non-palpable breast lesions. Their impact on short term quality of life

ABSTRACT Stereotactic biopsy and open biopsy represent useful diagnostic tools of breast lesions. However, both affect the Quality of Life (QoL) in various degrees. We conducted this prospective longitudinal comparative study in order, first to access the impact of these techniques on short-term QoL and second to compare and critically discuss our results with those of literature review. Group A (58 patients) underwent vacuum-assisted stereotactic biopsy and Group B (46 patients) underwent open biopsy. The Health-Related Quality of Life (HRQol) was estimated using the European Quality of Life scale (EuroQol) and the SF-36 (The 36-Item Short-Form Health Status Survey) questionnaires. The stereotactic breast biopsy seems to be more accepted from the patients as it affects quality of life to a lesser extent than open breast biopsy. This difference is mainly attributable to a reduction of physical discomfort and pain.

Visualization positioning-guided biopsy of suspicious breast microcalcifications: a retrospective cohort study.

BackgroundAt present, most histological evaluations of microcalcifications without a mass are performed using X-ray guided hook wire localization or vacuum-assisted stereotactic biopsy (VASB), but there are still several limitations to these techniques. Therefore, we designed a visualization positioning technique based on three directions of mammography to accurately locate suspected microcalcifications to guide the biopsy.MethodsWe retrospectively analyzed consecutive patients with suspicious microcalcifications who underwent visualization positioning-guided biopsy (VPB) from June 1, 2016, to June 1, 2021. The visualization positioning technique was performed using an electronic ruler to measure the vertical distance from the microcalcification core to the vertical lines on mammography.ResultsA total of 133 patients (median age 46 years; range, 22–87 years) who underwent VPB were included in our study. Among the 133 cases of microcalcifications based on pathological results, 104 were benign, 14 were high risk, and 15 were malignant. In 124 (93.2%) patients, microcalcification was confirmed during the first round of VPB specimen analysis. Only 6 (4.5%) and 3 (2.3%) patients underwent second and third extended resections, respectively, as the resected specimens did not contain microcalcifications. Four patients (3.0%) with malignant biopsy results underwent a subsequent operation. Two patients with DCIS underwent mastectomy and sentinel lymph node biopsy because of diffuse calcification. One patient had no residual cancer, and the other was upgraded to invasive ductal carcinoma (IDC). Two patients with IDC underwent breast-conserving surgery and mastectomy with sentinel lymph node biopsy.ConclusionsVPB can be used to evaluate breast microcalcifications when a mass is not present, making it an effective diagnostic technique.

Evaluation of Vacuum-assisted stereotactic biopsy for isolated BI-RADS 4 microcalcifications

Evaluation of Vacuum-assisted stereotactic biopsy for isolated BI-RADS 4 microcalcifications

Malignancy Rate and Malignancy Risk Assessment in Different Lesions of Uncertain Malignant Potential in the Breast (B3 Lesions): An Analysis of 192 Cases from a Single Institution

Background: The question of how to deal with B3 lesions is of emerging interest. Methods: In the breast diagnostics of 192 patients between 2009 and 2016, a minimally invasive biopsy revealed a B3 lesion with subsequent resection. This study investigates the malignancy rate of different B3 subgroups and the risk factors that play a role in obtaining a malignant finding. Results: The distribution of B3 lesions after minimally invasive biopsy was as follows: atypical ductal hyperplasia (ADH), 7.3%; flat epithelial atypia (FEA), 7.8%; lobular neoplasia (LN), 7.8%; papilloma (Pa), 49.5%; phylloidal tumour (PT), 8.9%; radial sclerosing scar (RS), 3.1%; mixed findings, 10.4%; and other B3 lesions, 5.2%. Most B3 lesions were detected by stereotactic vacuum-assisted biopsy (44.3%), 36.5% by ultrasound-assisted biopsy, and 19.3% by magnetic resonance imaging-assisted biopsy. Most B3 lesions (55.2%) were verified by surgical resection, whereas 30.7% were downgraded to a benign lesion. About 14.1% of the cases were upgraded to malignant lesions, 9.4% to ductal carcinoma in situ and 4.7% to invasive carcinoma. In relation to individual B3 lesions, the following malignancy rates were found: 28.6% (ADH), 13.3% (FEA), 33.3% (LN), 12.6% (Pa), 5.9% (PT), and 0% (RS). The most important risk factor was increasing age. Postmenopausal status was considered an increased risk for an upgrade (p = 0.015). A known malignancy in the ipsilateral breast was a significant risk factor for a malignant upgrade (p = 0.003). Conclusion: Increasing knowledge about B3 lesions allows us to develop a “lesion-specific” therapy approach in the heterogeneous group of B3 lesions, with follow-up imaging for some lesions with less malignant potential and concordance with imaging or further surgical resection in cases of disconcordance with imaging or higher malignant potential.

Ten years follow-up of histologically benign calcifications in the breast after vacuum-assisted stereotactic biopsy (VASB): Is additional mammographic follow-up warranted?

ObjectiveThis study assessed the short-term and the long-term breast cancer rate in patients with benign histopathologic results after a vacuum-assisted stereotactic biopsy (VASB) for calcifications. MethodsIn a retrospective cohort study, all consecutive patients who had a benign diagnosis after VASB to analyze breast calcifications. Data of breast cancer development at short-term (four years) and long-term follow-up was gathered. Breast cancer rates in our cohort were compared to the breast cancer incidence in the general population. ResultsOf 1376 patients who underwent VASB to analyze breast calcifications, 823 had a benign histopathologic diagnosis. During short-term follow-up, eight patients developed breast cancer. During the mean long-term follow-up period of 9.3 ± 3.1 years, 22 patients were diagnosed with ipsilateral breast cancer. The incidence rate of breast cancer after benign biopsy was comparable to the rate in the general population. ConclusionIn patients with VASB-confirmed benign calcifications of the breast, we found no excess incidence of ipsilateral breast cancer during ten years follow-up. Therefore, in patients with an increased risk of breast cancer (due to a history of breast cancer or familial risk) annual mammography should be sufficient. Patients with a population-based risk may be monitored via biennial mammography by the national screening program. More frequent screening would provide no benefit.

Identification of a localization wire tip in an occult breast lesion using a handheld magnetometer.

The Sentimag hand-held probe detects the magnetic response from iron oxide particles trapped in a sentinel node. To investigate if an electromagnetic probe can be helpful in the identification of a hook wire tip located in an occult breast lesion. Forty-two patients undergoing lumpectomy without axillary procedure were enrolled. In all cases, suspicious non-palpable microcalcifications without mass were found, and a vacuum-assisted stereotactic biopsy was performed. On the day of surgery, a traditional localization wire (LW) was placed under imaging guidance. The Sentimag magnetometer was used to precisely detect the wire tip through the skin. Then, the skin incision was made and Sentimag was used again to guide the surgeon to the lumpectomy bed. The accuracy of excision was assessed with intra-operative specimen 3D tomosynthesis. Median lesion size was 16 mm (range: 4-38 mm) and median depth was 33 mm (range: 14-78 mm). In all cases, the wire tip was successfully identified. Neither wire displacement nor transection occurred. Intraoperative radiography demonstrated doubtful margin requiring selective cavity shaving in 6 patients (14%). The need for cavity shaving was significantly influenced by the lesion size and histology: median size 30 mm (range: 24-38 mm) compared to 15 mm (range: 4-28 mm) and histology of ductal carcinoma in situ (DCIS) compared to atypical ductal hyperplasia (ADH) and lobular neoplasia (LN). Tumors requiring cavity shaving tended to be deeper - they had a median depth of 43 mm (range: 17-78 mm) compared to 32 mm (range: 14-76 mm) in patients who did not need cavity shaving, but this parameter was statistically significant. Intraoperative identification of the wire tip using Sentimag is a simple technique facilitating targeted excision without excessive removal of breast tissue. Since it is not associated with additional costs, it may be worth considering, particularly in developing countries.

Atypical Ductal Hyperplasia: Risk Factors for Predicting Pathologic Upgrade on Excisional Biopsy.

PurposeTo determine the incidence of atypical ductal hyperplasia (ADH) in needle biopsy and the upgrade rate to carcinoma, and to evaluate difference in findings between the upgrade and non-upgrade groups.Materials and MethodsAmong 9660 needle biopsies performed over 48 months, we reviewed the radiologic and histopathologic findings of ADH and compared the differences in imaging findings (mammography and breast US) and biopsy methods between the upgrade and non-upgrade groups.ResultsThe incidence of ADH was 1.7% (169/9660). Of 112 resected cases and 30 cases followed-up for over 2 years, 35 were upgraded to carcinoma (24.6%, 35/142). The upgrade rates were significantly different according to biopsy methods: US-guided core needle biopsy (US-CNB) (40.7%, 22/54) vs. stereotactic-vacuum-assisted biopsy (S-VAB) (16.0%, 12/75) vs. US-guided VAB (US-VAB) (7.7%, 1/13) (p = 0.002). Multivariable analysis showed that only US-CNB (odds ratio = 5.19, 95% confidence interval: 2.16–13.95, p < 0.001) was an independent predictor for pathologic upgrade. There was no upgrade when a sonographic mass was biopsied by US-VAB (n = 7)ConclusionThe incidence of ADH was relatively low (1.7%) and the upgrade rate was 24.6%. Surgical excision should be considered because of the considerable upgrade rate, except in the case of US-VAB.

Comparative analysis of digital breast tomosynthesis-guidedversus stereotactic vacuum-assisted biopsy

Comparative analysis of digital breast tomosynthesis-guidedversus stereotactic vacuum-assisted biopsy

Vacuum-assisted breast biopsy of microcalcifications on the stereotactic prone table and comparison of the histopathologic diagnosis with mammographic features

Aim: Breast cancer is one of the most important causes of mortality and morbidity in women. With the widespread use of screening mammography, the detection of non-palpable suspected cancerous lesions is increasing. Therefore, the use of vacuum-assisted breast biopsy in the management of breast lesions continues to increase. The aim of this study was to evaluate the histopathological results of suspicious microcalcifications which were diagnosed by vacuum-assisted needle biopsy on a stereotactic prone table and to compare the mammographic features of the microcalcifications with the histopathological results. Materials and Methods: The study included a total of 119 patients with a median age of 51 years (range, 33-77 years) who underwent stereotactic biopsy on a prone table because of suspicious microcalcifications between March 2010 and July 2014. Retrospective evaluation was made of the preoperative mammographic features, and the BI-RADS (Breast imaging-reporting and data system) scores of the microcalcifications and the vacuum biopsy and / or excisional histopathological results. Results: Stereotactic vacuum-assisted breast biopsy revealed that 52.1% of the lesions were benign and 47.9% were malignant. After vacuum-assisted stereotactic biopsy 61 patients underwent surgery. In 10 of these (16.3%) the final excisional histopathological diagnosis was benign, and in 51 (83.7%) malignancy was determined. Conclusion: Vacuum-assisted breast biopsy on a stereotactic prone table is a successful technique with a low failure rate for microcalcifications that are non-palpable and have no ultrasonographic findings.

Stereotactic Vacuum-Assisted Needle Biopsy Outcomes of Non-calcified Mammographic Lesions

To identify the outcomes of stereotactic vacuum-assisted large bore biopsies performed on sonographically-occult non-calcified mammographic lesions (NCL). In an IRB-approved retrospective study, we reviewed all NCL that underwent stereotactic biopsy from January 1, 2014 to December 31, 2017 at our institution, comparing patient age, lesion type, size and location with pathology outcome (benign, high-risk or malignant) using Wilcoxon-Mann-Whitney or Fisher's exact tests as appropriate. Multivariable logistic regression models were developed to decrease benign biopsies in our cohort with diagnostic performance assessed using receiver operating characteristic curve and area under the curve (AUC). Of 222 biopsied lesions in 213 patients, 79.3% (176/222) were benign, 5.9% (13/222) malignant, and 14.9% (33/222) high-risk. NCL were less likely to be malignant compared to calcifications biopsied in the same period [5.9% vs 19.0% (243/1279), p < 0.001]. All 42 asymmetries and 33 architectural distortions were benign, while 8.7% (4/46) of masses and 8.9% (9/101) of focal asymmetries were malignant. Cancers were associated with older age (mean 65.2 vs 52.7 years, p < 0.001), smaller size (mean 9.5 mm vs 15.5 mm, p < 0.01), and concurrent breast cancer (p < 0.01) compared to benign/high-risk lesions. Multivariable logistic regression model using patient age >50 years, lesion type, and size <15 mm had a high diagnostic performance [AUC=0.89, 95%CI (0.83, 0.94)], and yielded the highest PPV [0.24; 95%CI (0.13, 0.38)], and highest number of avoided, unnecessary biopsies (172/209, 82%). NCL biopsied under stereotactic guidance have low cancer yield (5.9%). A multivariate model integrating age, lesion size and type could potentially help avoid unwarranted biopsies in our cohort.

Clip migration after stereotactic vacuum-assisted breast biopsy with the patient in the decubitus position.

To investigate the factors contributing to clip migration in stereotactic vacuum-assisted biopsy (VAB) of the breast using an upright unit with the patient in the decubitus position. This retrospective study included 176 women with microcalcifications on mammograms undergoing stereotactic VAB with clip marking for analysis. The prebiopsy mammograms, stereotactic VAB images, immediate postbiopsy mammograms, and follow-up mammograms were reviewed. All VAB procedures were performed using an add-on upright unit with the patient in the decubitus position. The clip-to-lesion distance on the orthogonal view (craniocaudal view) on immediate postbiopsy mammography was estimated for each biopsy. Two cutoff points of clip-to-lesion distance of > 1cm or > 2cm were set for clip migration. The possible factors for clip migration based on clinical and imaging findings were then analyzed by Fisher's exact test. When the cutoff for clip migration was set at > 1cm, thin breast (p= 0.013) and more superficial lesion (lesion closer to the skin along the line perpendicular to the posterior nipple line, p= 0.004) were associated with clip migration. When the cutoff was set at > 2cm, thin breast (p= 0.019), high specimen number (p= 0.030), and posterior depth (p= 0.021) were associated with clip migration. Thin breasts, superficial lesion location, posterior lesion depth, and high specimen number were the factors associated with clip migration. • We reported clip migration after ST VAB using an upright unit with the patient in the decubitus position. • The occurrence of clinically significant clip migration (> 2cm) in our study was 8.5%, which was within the range of the other reports with the patient undergoing ST VAB in the prone position. • Thin breasts, high specimen number, and more posterior depth were the factors associated with significant clip migration.

P056: Post-biopsy cases of breast cancer where localisation is not possible - A clinical dilemma

Introduction: In patients with screen-detected breast lesions, stereotactic vacuum-assisted biopsy (VAB) is frequently used to diagnose cancer. Complications include haematoma, clip migration and excision of the index lesion. For cases where subsequent image guided localisation is not possible, there are no guidelines for management of these patients.

Cost-effectiveness of stereotactic vacuum-assisted biopsy for nonpalpable breast lesions

PurposeTo examine the potential cost-savings of stereotactic vacuum-assisted biopsy (SVAB) over open surgical biopsy (OSB) in diagnosis of nonpalpable lesions on mammography and to estimate the cost-saving effect on lesions at different levels of malignant probability. MethodsThis retrospective study was approved by our Institutional Review Board. We retrospectively reviewed 276 (33.8 %) SVAB and 541 (66.2 %) OSB medical records at a medical center. Direct costs included patients’ self-paid and national health insurance claim charges. Indirect costs were calculated using sick days, average salary, and age-adjusted employment rate. One-way and two-way sensitivity analyses were conducted. Lesion classification was determined by the assessment categories of Breast Imaging Reporting and Data System (BI-RADS), 4th or 5th editions. ResultsSVAB decreased the direct cost by $90.3 (10.1 %) per diagnosis. The indirect cost was decreased by $560.2 (96.0 %). Overall, SVAB saved 43.9 % of resource utilization for each biopsy. Taking the cost of the subsequent malignant surgery into account, from the healthcare providers’ perspective, SVAB was cost-effective if a lesion had less than 19 % likelihood of malignancy. From the societal perspective, SVAB reduced productivity loss for all the lesions. Based on the positive predictive value of the BI-RADS categories, SVAB was more suitable for the lesions of category 4A and category 3, resulting in greater savings in both medical and societal resources. ConclusionsSVAB is a cost-effective diagnostic option for nonpalpable breast lesions. The cost-saving effect is greater for the lesions of category 4A and category 3.