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Vacuum-assisted biopsy (VAB) of the breast is a minimally invasive diagnostic tool for breast interventions that has gained widespread acceptance as an alternative to surgical biopsy. VAB involves the use of a vacuum-powered probe and a specialized needle to remove tissue samples from the breast lesion under imaging guidance, allowing for accurate diagnosis with minimal tissue damage and scarring compared to surgical biopsy ^1,2.

The history of breast biopsy procedures has seen numerous technological advancements aimed at achieving more accurate diagnoses while minimizing invasiveness. Prior to the advent of Vacuum-Assisted Biopsy (VAB), Fine Needle Aspiration (FNA) and Core Needle Biopsy (CNB) were the primary methods for obtaining breast tissue samples ^3,4. However, both techniques had limitations, including issues related to under-sampling and false negatives, which could lead to inaccurate or uncertain diagnoses ^2,5,6.

Recognizing these limitations and the need for a more accurate and less invasive alternative to surgical biopsy, VAB was developed during the mid-1990s. Two significant contributors to this field were Dr. Burbank and Dr. Parker, who in collaboration with a multidisciplinary team, developed a purpose-built stereotactic breast biopsy instrument in 1993 ⁷, a 14-gauge needle with a coaxial system, specifically designed for tissue sampling. This marked a significant development in the evolution of breast biopsy techniques and the advent of vacuum-assisted biopsies. On August 5, 1994, the first stereotactic breast biopsy using this innovative device was performed at their center, a procedure subsequently referred to as “stereotactic mammotomy”⁷.

Early studies, such as that conducted by Parker et al. in 1997 ⁵, demonstrated that VAB could accurately sample breast lesions while minimizing complications. Over the subsequent years, VAB has undergone further evolution in terms of needle design, imaging guidance, and overall performance. These advancements have resulted in the widespread acceptance of VAB as a standard diagnostic tool in breast interventions.

The VAB equipment is specifically designed to facilitate accurate targeting and sampling of breast lesions. These devices can incorporate either wire or wireless guidance systems, which assist in guiding the biopsy needle to the intended target lesion.

During a VAB, the procedure combines tissue aspiration and cutting mechanisms to collect tissue samples. The vacuum assistance within the VAB system plays a crucial role by creating suction within the needle. This vacuum suction draws the tissue into the needle aperture, providing stability during the sampling process. Once the tissue is drawn into the needle, a cutting mechanism is utilized to remove the tissue sample. The specific cutting mechanism may vary depending on the VAB device being used but commonly involves a rotating cutter or a similar mechanism within the needle. The cutter is activated to rotate or oscillate, effectively cutting through the tissue inside the needle and separating a sample from the surrounding tissue.

The integration of vacuum assistance and the cutting mechanism enables controlled and precise sampling of the tissue. The vacuum holds the tissue securely, minimizing the risk of sample contamination or displacement during the cutting process. The cutter ensures a clean and accurate separation of the tissue sample from the rest of the lesion, contributing to the overall success of the biopsy procedure.

VAB provides superior control and precision during biopsy compared to automatic CNB devices. For instance, VAB eliminates needle tip excursion during the procedure, ensuring continuous operator control of the needle cannula within or beneath the targeted lesion. Moreover, the large sampling volume of the VAB cannula enables reliable sampling of small masses, which can be challenging with multiple CNB passes, especially for less experienced operators. VAB offers several additional advantages over CNB:

1. Accuracy: VAB has been shown to provide more accurate diagnoses than CNB, with lower underestimation rates in cases with DCIS ⁸. The larger sample size obtained by VAB improves diagnostic accuracy and reduces the need for surgical excision in case of benign findings ⁹.
2. Sample Size: Unlike CNB, which obtains a small tissue sample, VAB uses vacuum assistance to draw and cut a larger tissue sample, providing more material for pathological analysis ⁶.
3. Reduction in Sampling Errors: VAB has been reported to decrease the rate of sampling errors¹⁰. CNB carries a greater risk of inadequate sampling, which could potentially lead to an incomplete representation of the disease’s extent and consequently, a higher chance of false negatives ¹¹.
4. Management of High-Risk Lesions: VAB improves the management of high-risk lesions by reducing underestimation rates, particularly for certain B3 lesions, such as Lobular Neoplasia (LN), Flat Epithelial Atypia (FEA), radial scar, and papillary lesions, when specific criteria are met. However, it is important to note that surgical excision remains the primary treatment approach for Atypical Ductal Hyperplasia (ADH) ^12,13.

The decision to perform a VAB on patients and target lesions is based on various factors, including the radiographic features of the lesion, the patient’s clinical history, and the limitations associated with alternative biopsy techniques. VAB is frequently utilized for lesions demonstrating specific characteristics, such as microcalcifications, architectural distortions, and other radiographically suspicious findings that may pose challenges for sampling with CNB ¹.

Some specific indications for VAB:

• The decision to perform a VAB on patients and target lesions is based on various factors, including the radiographic features of the lesion, the patient’s clinical history, and the limitations associated with alternative biopsy techniques. VAB is frequently utilized for lesions demonstrating specific characteristics, such as microcalcifications, architectural distortions, and other radiographically suspicious findings that may pose challenges for sampling with CNB ¹.
• Lesions with suspicious or indeterminate imaging features, such as microcalcifications, architectural distortions, or asymmetries, where VAB can help determine the need for further treatment or surgery ^15–17.
• Known or suspected high-risk lesions, such as atypical ductal hyperplasia (ADH), atypical lobular hyperplasia (ALH), lobular carcinoma in situ (LCIS), radial scar, or papillary lesions, to evaluate the extent of the lesion and exclude the presence of malignancy ¹².
• Reassessing previously benign biopsies with persistent imaging-pathology discordance, interval changes, or inconclusive initial results due to insufficient sampling ^18,19
• Monitoring of neoadjuvant chemotherapy response in breast cancer patients by performing VAB after treatment, showed promising early results, pending further trials to better define protocols and future guidelines ^20–22.

VAB can be performed using different image guidance modalities, depending on the specific clinical scenario and available equipment. The commonly utilized mammographic guidance modalities for VAB include ultrasound conventional stereotaxy and digital breast tomosynthesis (DBT)-guided biopsy. Conventional stereotaxy involves obtaining two-dimensional mammography images from different angles to localize the lesion in three-dimensional space. The stereotactic unit uses these images to guide the biopsy needle to the target lesion, demonstrating high diagnostic accuracy rates and widespread use for VAB guidance ^23,24.

Stereotaxy guidance

Ultrasound guidance

Photos used with the express permission of the author

Tomosynthesis or DBT-guided biopsy utilizes digital breast tomosynthesis, capturing multiple low-dose mammography images from various angles to create a three-dimensional image of the breast. This modality has shown promise in improving diagnostic accuracy and reducing the need for additional imaging or biopsy procedures ^25–27.

Tomosynthesis guidance

Photo used with the express permission of the author

In addition to mammographic guidance modalities, MRI guidance can be employed for VAB in cases where the MRI findings indicate the need for a biopsy due to a lack of correlation with other imaging techniques. MRI guidance allows for precise targeting and effective sampling of these specific findings ^28–30.

MRI guidance

Photo used with the express permission of the author

Furthermore, a contrast-enhanced mammography-guided biopsy (CEM-guided biopsy or contrast-enhanced stereotaxy) has been implemented, initially for indications similar to MRI ³¹. This modality involves the administration of an iodinated contrast agent, through intravenous injection, to enhance the visualization of the lesion and surrounding tissues on mammography images. A CEM-guided biopsy can help identify small or subtle lesions and improve the accuracy of VAB by enhancing lesion localization and reducing the chance of sampling error.

Photo used with the express permission of the author

The choice of the most appropriate mammographic guidance modality depends on the specific clinical scenario, characteristics of the lesion, and equipment availability. The goal is to achieve accurate lesion localization, optimal sampling, and minimize patient discomfort and radiation exposure.

Needle gauge and size are vital determinants in VAB procedures, available typically from 7G to 14G. The choice hinges on several factors, such as lesion attributes (size and location), patient considerations, and the operator’s preference.

Compared to CNB, VAB usually yields larger sample sizes for pathological assessment. Larger diameter needles (smaller gauge, 7G to 8G), are typically used for lesions requiring a higher volume of tissue sample, whether for diagnosis or excision purposes. Conversely, smaller diameter needles (larger gauge, 10G to 14G) provide lower amounts of tissue. Under certain circumstances, a 14G needle, the smallest VAB gauge available, might be chosen for lesions near critical structures to mitigate risk.

Surgical biopsy traditionally involves an average of 20 g sample size. Given that VAB often yields samples around 5-10 g, with a more targeted acquisition due to image guidance, some studies suggest that its sensitivity could be comparable to surgical biopsy ³². Earlier research indicates that the 11G probe collects around 100 mg of tissue per procedure, while the 14G core probe collects approximately 15 mg per sample ³³. The 7G needle, currently the broadest diameter option available, is known to obtain more substantial sample sizes [2]. However, other elements such as the needle’s structure, the strength of the suction, and the suction’s duration also play a role in determining the sample size. Similarly, the hardness of the lesion targeted for biopsy also impacts the sample collection process. VAB can obtain larger samples from softer lesions than harder ones ³³. Despite the lack of consensus on the sample amount, common practice suggests collecting over 10-12 specimens using a 10-11G needle or 4-6 specimens using a 7-8G needle.

Clip placement is a crucial aspect of VAB procedures, particularly in cases where the targeted lesion is otherwise occult or may faintly appear or disappear after the biopsy procedure. Radiological markers, such as tissue markers or clips, are used to localize the biopsy site and provide important reference points for future imaging and follow-up ³⁴.
Radiological markers serve multiple purposes in VAB:

• Localization: Placing a radiological marker, typically a clip, at the biopsy site, ensures accurate localization of the area where the tissue sample was obtained. This is particularly important when the lesion is not readily visible on imaging or when there is concern about its visibility post-biopsy.
• Follow-up and Surveillance: The presence of a radiological marker allows for easier identification of the biopsy site during follow-up imaging. It provides a reference point for monitoring the area of interest and assessing changes over time. The marker aids in distinguishing between post-biopsy changes and any potential residual or recurrent lesions.
• Surgical Guidance: In cases where VAB results indicate the need for surgical excision, the placement of a radiological marker facilitates precise localization of the targeted area during subsequent surgical procedures. This ensures that the surgical team can accurately identify the site of concern and perform the necessary excision with minimal tissue removal.

Radiological markers used in VAB procedures are typically small, inert clips made of materials that are visible on imaging, such as titanium or stainless steel. These clips are carefully placed under imaging guidance, ensuring accurate positioning relative to the targeted lesion. The radiological markers are generally well-tolerated by the patient and do not interfere with subsequent imaging or treatment ^34,35. The main complication is marker migration after deployment ^36–38 and therefore is important to assess adequate positioning in post-procedure mammography.

Photos used with the express permission of the author

VAB is a safe and minimally invasive procedure, with a low risk of complications. The most common complications include skin tear, pain, bruising, and hematoma at the biopsy site, which usually resolves spontaneously within a few days. The incidence of serious complications, such as bleeding, infection, or pneumothorax, is rare and seen in only 0.3% of patients ³⁹.

To minimize the risk of complications, careful patient selection, appropriate needle size, and proper technique are essential. A thorough evaluation of the patient’s coagulation status and the use of local anesthesia with epinephrine can also help reduce the risk of bleeding ⁴⁰. Additionally, while performing the biopsy, it is important to ensure accurate placement of the needle and to monitor for potential complications in real-time.

In cases of bleeding or hematoma, compression and observation are often sufficient for management. However, if the bleeding is persistent or severe, additional interventions such as embolization or surgical exploration may be necessary. Infection can be treated with antibiotics, and in rare cases, abscess drainage may be required.

Nipple discharge, an unusual complication, can often be managed conservatively, but persistent or suspicious discharge may require further evaluation.

Another potential complication of VAB is the development of biopsy-related artifacts on subsequent mammography, which can mimic distortions or calcifications and potentially lead to unnecessary additional procedures, although this is not usually a problem. To minimize the risk of equivocal interpretation, it is important to carefully document the biopsy location and technique.

To minimize the risk of complications, including skin tears or hematomas, during the VAB procedure, it is essential to exercise caution and take necessary precautions. The combination of the vacuum system and compression from the ultrasound probe can potentially lead to a skin tear. Therefore, maintaining clear visualization of the needle and utilizing ultrasound guidance throughout the procedure are crucial steps. Adequate local anaesthesia should also be provided to ensure patient comfort. By adhering to these measures, the aim is to prevent complications and ensure the safe and successful completion of the VAB procedure.

VAB is a widely accepted minimally invasive diagnostic tool for breast interventions. It offers advantages such as improved accuracy, larger sample sizes, and reduced sampling errors compared to traditional biopsy methods. The appropriate patient selection and imaging guidance modality are critical to ensure optimal sampling and minimize complications. VAB can be performed under different image guidance modalities, including conventional stereotaxy, digital breast tomosynthesis (DBT)-guided biopsy, MRI guidance, and contrast-enhanced mammography-guided biopsy (CEM-guided biopsy). Needle size and gauge should be chosen based on lesion characteristics and patient factors, with larger needles preferred for larger lesions or those requiring more tissue sampling. Complications of VAB are rare and usually minor, and the procedure is generally well-tolerated by patients. VAB has revolutionized breast biopsy, enabling accurate diagnoses with minimal tissue damage and improved procedure outcomes.