Breast Biopsy and Ablation

Rationale for Minimally Invasive Biopsy

Minimally invasive, image-guided breast biopsy is the standard of care for tissue acquisition and definitive diagnosis of indeterminate breast lesions identified with imaging, whether palpable or nonpalpable. According to the American Society of Breast Surgeons, as well as the American College of Radiology, open surgical biopsy should be reserved for cases in which image-guided biopsy cannot be performed because of either lesion or patient factors. Percutaneous, image-guided biopsies are less invasive; have lower cost, fewer complications, and faster recovery times with minimal to no scarring ; and result in equally accurate diagnoses compared with surgical excisional biopsy. Studies have demonstrated that in patients with breast cancer, minimally invasive breast biopsy before definitive surgery results in fewer surgeries when compared with those who undergo open surgical biopsy.

All lesions warranting biopsy should be sampled with a percutaneous approach, even if highly suspicious for malignancy, as establishing a preoperative diagnosis of malignancy will allow for consideration of additional imaging, optimize surgical approach, and maintain eligibility for possible neoadjuvant chemotherapy. Additionally, genetic testing, plastic surgery, and fertility consultations can be obtained preoperatively, which can significantly impact management. Oncologic and cosmetic outcomes are optimized with preoperative diagnosis, as well as axillary biopsy before definitive surgery, which can alleviate the need for a second surgical procedure for nodal sampling when clinically indicated. Additional treatment-planning information such as estrogen and progesterone receptor status, HER2 status, and Oncotype DX scores can be ascertained on a core needle biopsy (CNB). Such assessment can aid with patient counseling and treatment options before surgery. Studies have shown that when a diagnosis of cancer is known before lumpectomy/partial mastectomy, negative margins are more frequently achieved. Additionally, preoperative CNB can reduce the need for repeated surgeries to evaluate and/or treat the axilla in the case of a diagnosis of invasive disease.

Preprocedure Considerations

The considerations for minimally invasive biopsy include which imaging modality will guide the biopsy and what type of biopsy device should be used. Any lesion that is visible with US should usually undergo biopsy with US guidance—even if seen with other imaging modalities—because of the absence of ionizing radiation, continuous real-time visualization, increased patient comfort, decreased cost, and increased speed. Additionally, US provides greater accessibility to the axilla and subareolar regions, and allows for rapid sampling of multiple lesions. If a lesion is not visible with US but is mammographically visible, stereotactic biopsy is used. If a lesion is not visible with either US or mammography, but only with MRI or BSGI/MBI, then these imaging modalities should guide the biopsy. If a lesion is seen with multiple imaging modalities, but is more reliably seen in one, then the modality that best visualizes the lesion should be chosen to guide the biopsy.

With regard to the type of biopsy device chosen, the options include fine-needle aspiration (FNA), CNB, and vacuum-assisted biopsy (VAB). Although FNA was commonly used to sample breast lesions early in development of percutaneous breast procedures, it is now used infrequently due to the additional expertise and training required on the part of the pathologist and the frequent result of insufficient samples, ranging from 15% to 74%. Currently, FNA is reserved for masses that may not be safely sampled with CNB, such as lesions near a breast implant or sternum that cannot safely undergo biopsy with CNB, therapeutic drainage of symptomatic benign cysts, or for abscesses where fluid is sent for culture. CNB is now preferred because it yields a surgical-quality specimen with a rapid and cost-effective technique. CNB has also been shown to be more accurate and require fewer repeated procedures than FNA when used for axillary lymph node sampling. CNB has minimal complications combined with less variability and improved sensitivity and specificity.

The use of directional VAB devices is standard for stereotactic/tomosynthesis biopsy, as well as for MRI- and BSGI/MBI-guided biopsy. However, VAB can be useful in the US setting as well, particularly in small and subtle lesions that may become difficult to visualize after initial sampling or for intraductal/intracystic masses. When planning US biopsy with VAB, care should be taken to allow enough distance from the skin, typically at least 1 cm, to avoid unintentional skin biopsy. In some practices, all minimally invasive breast biopsies are performed with VAB. Although somewhat more invasive, their use is associated with lower upgrade rates at subsequent surgical excision and the ability to obtain multiple samples with one device insertion. The decision as to which type of biopsy device to use is made by the radiologist and the practice. Regardless of the type of biopsy or the device used, concordance with pathology and appropriate clinical follow-up are necessary steps for a successful breast biopsy.

Procedure Discussion with Patient

When discussing the procedure with a patient, it is important to choose words carefully, aiming for clarity and reassurance. We often describe the procedure as “tissue sampling” and avoid language such as “cutting,” and instead of a “biopsy gun,” we favor a more neutral term such as “sampling device.” Although most lesions that undergo biopsy are benign, it is nevertheless important to choose verbiage that is appropriate to each patient’s situation. For example, with Breast Imaging and Reporting Data System (BI-RADS) category 4A or 4B lesions, we discuss the positive predictive value of minimally invasive breast biopsy, although in the case of a BI-RADS 5 lesion, it is more prudent to prepare the patient by discussing the probability of cancer, so the patient can then bring a supportive family member or friend when they obtain their results. Additionally, we always discuss the placement of the biopsy marker. In fact, we require that patients initial the consent form where it describes the biopsy marker so that there is no question that this issue was fully discussed.

It is important for the patient to have accurate expectations of when the pathologic results will be available to them and how they will get the results, whether it is from the radiologist, as occurs in our practice, or from their referring provider. It is important to describe the possible pathologic outcomes: benign, malignant, or atypical. We often tell patients that a result of atypia means the cells are not normal but are not cancer. However, there may be malignant cells adjacent to the atypical cells, and therefore surgical excision may be necessary. If a diagnosis of atypia is found and surgical excision is recommended, this discussion before the biopsy can help foster reasonable expectations on the part of the patient.

Finally, how patients obtain their pathology results is rapidly changing. With implementation of the patient transparency requirements of the Affordable Care Act, patients are increasingly obtaining their results directly from the electronic medical record that is available to them. This is the case in our practice; therefore, we now discuss that the pathology will be available directly to the patient at the same time that it is released to the physician. This is a marked change because, increasingly, patients are learning of their breast cancer from accessing their electronic medical record. Explaining this and how patients can reach the physician to further discuss results and next steps is now part of our consent process.

Complications and Contraindications

Percutaneous, image-guided breast procedures are low risk with few complications, most commonly bleeding and infection, and newer studies suggest that complications are extremely rare—as low as 0.3%. In a 13-year study of 4776 patients, the rate of return to annual screening after biopsy was not adversely affected by the presence of procedural complication.

A frequent question is whether to discontinue anticoagulant or antiplatelet therapies before the biopsy. Research has shown no difference in hematomas in patients undergoing breast biopsy whether they were fully anticoagulated or not. However, it remains good practice to advise patients of the possibility of hematoma if they are on antiplatelet or anticoagulant therapies. To minimize the risk of bleeding when anesthetizing deeper breast tissue, it is common to use lidocaine with epinephrine, which causes both vasoconstriction and prolongs the anesthesia while reducing the systemic concentration. At the conclusion of the procedure, holding continuous pressure for about 5–10 minutes aids with hemostasis, particularly after biopsies that use a larger-gauge needle and/or prone positioning of the patient. Rarely, placement of a stitch, generally by the surgeon, is necessary to achieve hemostasis.

Other complications include the rare infection, treated with antibiotics, as well as persistent pain, which decreases with time. To mitigate the risk of infection, the overlying skin should first be disinfected, and sterile gloves and equipment, including probe covers when using US guidance, should be used. There can occasionally be mammographic sequelae after minimally invasive breast biopsy presenting with architectural distortion, particularly when using larger-gauge needles and taking a greater number of samples. The presence of the clip placed at the time of biopsy can identify that any mammographic sequelae are the result of the biopsy.

Contraindications to minimally invasive breast biopsy include a patient’s inability to physically cooperate with the examination (i.e., inability to lie prone for at least 30 minutes for MRI-guided biopsies) and patient weight exceeding equipment capability (typically 300–350 lb) for prone stereotactic or MRI-guided biopsy. Additionally, a thinly compressed breast, less than 2 cm, can result in a challenging stereotactic biopsy, as can a very posterior lesion with MRI-guided biopsy. This condition is discussed later in this chapter.