Needle core biopsy has proven its accuracy in comparison to open surgical biopsy and is considered “best practice” for mammographically detected abnormalities. Said a panel of experts in 2009, it should be considered the “gold standard” for initial diagnosis and should essentially replace open surgical biopsy. The panel recommended changing practice protocols if practices are still using open surgical biopsy as their standard diagnostic tool for mammographically found abnormalities. They also suggested that surgeons should have an open surgical biopsy rate for initial diagnosis of approximately 5% - 10%. Additional recommendation was made that stereotactic mammographic guided biopsy with specimen radiography is the most appropriate biopsy technique for calcifications and lesions not visible on ultrasound (US). They also recommended that vacuum-assisted biopsy devices should be used to minimize sampling errors and underestimation of disease. The insertion of tissue markers at biopsy completion was recommended for all patients, as this localizer is in place for patients with, biopsy proven malignant lesions, and large malignancies undergoing pre-surgical chemotherapy. The panel suggested the use of different tissue markers with different configurations when multiple biopsies in the same breast are performed for accurate lesion identification. (1)
Stereotactic guided breast biopsy is now commonplace in breast disease diagnosis. This CME will provide an overview of the stereotactic breast biopsy accreditation process and provide common examples of positioning, examination pitfalls and the importance of tracking biopsy outcomes.
STEREOTACTIC BREAST BIOPSY: ACCREDITATION PROCESS
All information discussed in this section can be found on the ACR website at www.acr.org and is very helpful for a successful submission. (2)
The American College of Radiology’s (ACR) stereotactic breast biopsy accreditation program offers peer review and constructive feedback for facilities that provide stereotactic breast biopsy to their patients. The stereotactic accreditation program is voluntary. One might think, if it’s voluntary, why do it? Participating in the program demonstrates a facility’s commitment to providing the best patient care. When a facility offers these services and the voluntary ACR accreditations are obtained, such as breast Ultrasound, and breast Magnetic Resonance Imaging (MRI), the facility can be designated an American College of Radiology Center of Excellence. The accreditation processes are time consuming for the site and are designed to deliver feedback on staff’s training and qualifications, quality control and assurance, accuracy of procedures, image quality and dose to the patient. This is an active statement to the patients of the facility’s commitment to deliver the highest quality breast care, as well as providing transparency in processes and standards. As with the other imaging accreditations, the stereotactic process requires clinical and phantom images for each stereotactic biopsy unit at a facility (dedicated stereotactic unit or mammography unit with the stereotactic add on), as well as all the other required documents needed for review. Like other modality accreditations, the process is subject to timelines; 45 days to submit required material, and is unit based, so if the facility has several stereotactic units, all required information will be need to be submitted for each unit. Once the preliminary information for the biopsy accreditation has been processed, the supervising physician at your site will receive a letter along with the submission testing materials. The submission materials included in the packet are; quality assurance questionnaire, testing instructions, test image data sheet (to be completed for each unit), technologists’ quality control (QC) forms, testing materials checklist, identification labels for all images (these will have the forms and QC data, dosimeters specifically assigned to each unit, and mailing envelope to send dosimeters to Landauer). If the facility is a new accreditation applicant, the stereotactic breast biopsy quality control manual is also provided. It is very important that the staff involved with this process become acquainted with all the requirements, as the process needs to be followed very carefully. Incomplete submissions will delay the process. The process can be expensive as the fees are unit based.
Personnel Requirements for ACR accreditation
The ACR stereotactic breast biopsy accreditation site provides a list of the specific qualifications (initial, continuing experience, and continuing education) required for the interpreting physician (independent and collaborative settings), radiologic technologist, and medical physicist. All physicians, technologists, and physicists working in stereotactic breast biopsy “must meet and document” the necessary requirements to be accredited by the ACR.
First and foremost, the radiologist, technologist, and medical physicist must be Mammography Quality Standards Act (MQSA) qualified and meet the continuing education required for MQSA. The continuing education and experience requirements are based on the previous 3 full calendar years.
Physicians who work in a collaborative setting refers to situations in which both a radiologist and a surgeon (or other physicians) perform stereotactic breast biopsies. Both parties have the responsibility of selecting patients for stereotactic biopsy, and quality assurance which would include information for the medical audit. The radiologist is solely responsible for the interpretation of the mammogram, oversight of the stereotactic quality control and quality assurance procedures, and is the supervising physician for the technologist and physicist. The radiologist in a collaborative setting must meet the initial criteria of having; performed 12 stereotactic biopsy procedures or 3 hands on procedures under a qualified physician, 3 hours of category 1 Continuing Medical Education (CME) credits in stereotactic breast biopsy, experience in stereotactic core biopsy recommendations, lesion identification at time of biopsy, and be qualified under MQSA as an interpreting physician. The “other physician” in a collaborative setting must meet the initial criteria of having; performed 12 stereotactic biopsy procedures or 3 hands on procedures under a qualified physician, 3 hours of category 1 CME credits in stereotactic breast biopsy (including image triangulation for lesion location), and post biopsy patient management experience. Continuing experience for renewal needed for both include; meeting the requirements for the American Board of Radiology (ABR)/American Osteopathic Board of Radiology (AOBR) or having 36 image guided biopsies within the previous 36 months with at least 9 being stereotactic core biopsies. Renewal of continuing education for both require meeting the requirements for the ABR/AOBR or having 150 hours relevant to the physicians practice (which includes 75 hours of category 1 CME) in the previous 36 months or have completed 15 CME hours (half of which are category 1) in the past 36 months that are specific to the breast (stereotactic biopsy or breast).
An interpreting physician in an independent setting is the setting where a radiologist or another physician, usually a surgeon, performs the stereotactic breast biopsy. This physician is responsible for; selecting appropriate patients for stereotactic biopsy (which would include documentation of clinical breast exams), oversight of quality control and quality assurance (which includes the medical audit), supervision of the technologist and physicist, and post biopsy management of the patient. In addition to the responsibilities listed above, a radiologist in an independent setting will be responsible for the interpretation of the mammogram, documentation of breast examinations, and referring patients to surgery for applicable lesions. The radiologist’s initial qualifications in this independent setting are performing 12 stereotactic biopsy procedures or 3 hands-on procedures under a qualified physician, 3 hours of category 1 CME credits in stereotactic breast biopsy, 15 hours of category 1 CME in breast imaging (benign and malignant disease and clinical breast examination), and be qualified under MQSA as an interpreting physician. ABR and AOBR requirements for continuing experience must be met or 36 image-guided breast biopsies with at least 9 stereotactic breast biopsies in the past 36 months. The “other physician” initial qualifications in an independent setting are performing 12 stereotactic biopsy procedures or 3 hands on procedures under a qualified physician, 15 hours of category 1 CME in stereotactic breast imaging/biopsy or 3 years of experience with at least 36 stereotactic breast biopsies, 4 hours of category 1 CME credits in medical radiation physics and has consulted with a MQSA qualified physician in the evaluation of 480 mammograms within the prior 2 years. Continuing experience necessitates having performed 36 image-guided breast biopsies with least 9 stereotactic breast biopsies in the past 36 months and has consulted with a MQSA qualified physician in the evaluation of 720 mammograms. Both the radiologist and “other physician” in an independent setting must show meeting ABR and AOBR requirements or have 150 hours relevant to the physicians practice (which includes 75 hours of category 1 CME) in the previous 36 months or has completed 15 CME hours (half of which are category 1) in the past 36 months that are specific to the breast (stereotactic biopsy or breast) for continuing education.
Radiologic Technologist Requirements
Like the radiologist, the technologist assisting with stereotactic breast biopsy must be qualified under MQSA and it is recommended that the individual is also certified and registered in breast imaging. Initial qualifications include: MQSA qualified to perform mammography, 3 category A CME credits in stereotactic biopsy and has performed 5 stereotactic breast biopsy procedures under supervision of qualified personnel (physician or technologist). When renewing accreditation, the technologist must show continuing experience by having assisted with 24 stereotactic biopsy exams in 24 months. Continuing education requirements for registered technologists are: continued compliance with CME requirements, with recorded CMEs applicable to the ACR accredited clinical practice. For state-licensed technologists and all others requirements include: 24 CME credits ever 2 years, recorded CMEs are applicable to the radiology sciences and patient care, and the recorded CMEs are applicable to the ACR accredited clinical practice.
The medical physicist performing surveys on stereotactic breast biopsy equipment must be qualified under MQSA. Initial qualifications include that they must be able to perform mammography surveys under MQSA and have performed 1 stereo survey under a qualified physicist or at least 3 stereo surveys on his/her own before 6/1/1997. Continuing experience for physicists for renewal is having performed 2 stereo surveys within the last 24 months and continuing education for renewal is 3 Continuing Education Units (CEU) in stereotactic breast biopsy in the prior 36 month.
The ACR accreditation program only accredits stereotactic units with the following specifications: dedicated stereotactic breast biopsy units, mammography units with add-on stereotactic devices for breast biopsy, mammography units using a lateral arm device (only if the arm device is the only option for biopsy and the needle can be seen in relation to the target).
Quality control record documentation of acceptance testing and annual surveys is required. The annual survey quality control tests consist of: unit assembly mechanical component check, collimation assessment, focal spot, spatial resolution, kVp accuracy and reproducibility, half value layer assessment, automatic exposure control and/or manual exposure performance assessment, receptor speed uniformity, breast entrance exposure, average glandular dose, exposure reproducibility, image quality evaluation, artifact evaluation, and localization accuracy test. Additionally, daily, weekly, monthly, quarterly and semiannual quality control tests performed by the radiologic technologist should be documented as part of the accreditation process. These tests include but are not limited to; daily localization accuracy test, daily compression accuracy test, weekly phantom images, monthly hardcopy output quality test, visual checklist of mechanics and stability of the system, semiannual compression check and repeat analysis for digital system users. There are additional tests required for those that use film-screen such as: daily darkroom cleanliness and processor quality control, weekly screen cleanliness and view box check, quarterly fixer retention analysis, semiannual screen film contact test and darkroom fog test. Specific manufacturers may require additional tests, such as the zero-alignment test prior to each patient. These are considered part of quality control. Suggested preventive maintenance should be performed by qualified field engineers and documented as part of the stereotactic unit’s record.
Stereotactic biopsy outcome audit documentation is mandatory for facilities and will be requested in the application. The audit information requested will consist of the total number of procedures performed, total number of cancers found, total number of benign lesions, and total number of repeat stereotactic biopsies, along with the reason for the repeat. The reasons should be listed under insufficient sample, discordance, cellular atypia/radial scar, or other and each should include the number of cases involved, the number with repeat core biopsy, the number referred to open excision and the final pathology. Complications resulting from the stereotactic biopsy that led to treatment will also need to be included in your medical audit and should include; the total number, and the total number of hematomas and infections.
Images and Paperwork
Once the initial application is processed, a packet will be mailed to the facility. It will include all the necessary paper work, testing materials and image labels for submission and the site will have 45 days to submit to the ACR. One microcalcification stereotactic biopsy case with proper needle placement is to be submitted. There is an option to send either the pre-biopsy or post-biopsy stereo images, along with the specimen radiograph. In addition to submitting the biopsy images, the corresponding mammogram should also be submitted and should have been acquired within 60-days before the stereotactic biopsy was performed. This case should be an example of the facility’s best work and easily identifiable on both the stereotactic procedure and the mammogram. All images must include appropriate labeling and identification. Part of the required labeling includes the patient’s first and last name, identification number, examination date, and breast designation (right or left). The ACR packet will include labels that will need to be placed on the images. If any of the required information is missing, the case will be failed. Images should also include the name of the facility, image annotation, and technologist initials; however, these are not required identifiers. Figure 1a-i demonstrates an excellent case choice for submission as there are easily visible microcalcifications on mammography and the stereotactic unit.
Figure 1a-b. Microcalcifications are easily visible on mammography. Click on image to enlarge
Figure1c. Scout demonstrates calcifications.Click on image to enlarge
Figure 1d-e. Stereo pair demonstrates the target. Click on image to enlarge
Figure 1f-g. Prefire stereotactic pair demonstrates accurate placement of the biopsy needle. Reminder that only a pre or post fire or post biopsy stereo pair is required for submission. Click on image to enlarge
Figure1h. Post biopsy cavity is demonstrated with adequate positioning of the tissue marker. Click on image to enlarge
Figure1i. Post biopsy specimen radiograph demonstrates that an adequate amount of microcalcifications were retrieved Click on image to enlarge
The ACR and the facility should have a Health Insurance Portability Accountability Act (HIPAA) compliant business associate’s agreement in place to allow for the collection of patient information for accreditation purposes. Facilities should check to see if this is in place and if not, should contact the ACR to get one executed prior to case submission.
Phantom images must be obtained from one of three ACR approved stereotactic breast biopsy accreditation program phantoms. Two or more physicists trained by the ACR will review and score the images. Minimum scores are required for passing and depend on the phantom used, whether it was digital or screen-film, and the average glandular dose, which must not be over 300 mrad.
The process to review the submission takes approximately 90 days and sites will be notified of the results by mail. If a site does not pass, the entire process does not have to be repeated, only the areas that did not pass will need to be resubmitted and additional fees will apply. Additionally, facilities can appeal a failed submission in writing within 15 days. An arbitrator (not involved in the initial review) will be chosen to review the images, the previous reviews, and the site’s appeal letter. The arbitrator’s review decision will be final.
This entire process usually takes approximately 4 to 6 months and facilities should get the process started well before existing accreditation expires. The ACR will usually notify sites of pending renewal, but renewal dates should be on the staff’s radar.
On-site surveys can occur anytime during the 3-year period of accreditation or during the accreditation process. These are to ensure that the facility is maintaining all the required elements of accreditation.
All this information and more can be found on the accreditation website.
STEREOTACTIC BREAST BIOPSY: CASE REVIEW
Who fits the criteria for stereotactic biopsy?
Patient selection and attention to detail during the stereotactic biopsy procedure will eliminate many potential problems, however examination pitfalls still exist even with the best attempts. This next section will address some of the common issues that occur with a prone stereotactic biopsy unit.
Typically, non-palpable abnormalities classified as a Breast Imaging Reporting and Data System (BI-RADS) 4 or 5 (suspicious/highly suspicious-requires biopsy) not seen by ultrasound will be biopsied under stereotactic guidance. Sonography has become so advanced that it can identify most abnormalities when targeting to the specific area of interest, but limitations still exist with imaging microcalcifications, asymmetries, architectural distortions, and some masses. (3) When this occurs, stereotactic biopsy is the preferred option. Unfortunately, not all patients can undergo a biopsy with this method. Weight that exceeds the limit for prone tables (ability to perform this procedure with an upright stereotactic biopsy is helpful if a facility has access to both prone and upright), thinly compressed breast thickness, and medical issues that do not allow for study compliance are all factors that make the patient ineligible for stereotactic biopsy. Open surgical biopsy is often recommended in these instances, however, those experienced in stereotactic biopsy can develop some adjustments for success.
Often an attempt at stereotactic biopsy will occur before open surgical is recommended. For patients that are close to the weight limit, a successful biopsy can be performed if you do not raise the table, as the weight limit of “table down” is higher, at 350 pounds. For breast thickness issues, in cases where there is not enough breast thickness to use the standard needle trough, a petite needle can be utilized. In addition, repositioning the breast in nonstandard positions may provide a greater amount of breast tissue to allow the needle biopsy to be performed. Superficial abnormalities can also be problematic, as the needle trough needs to be completely covered. Even in a thin breast the radiologist can gain some breast tissue thickness by creating a large lidocaine wheal under the skin for the local anesthesia. This can give you as much as one cm or more of tissue to cover the trough of the vacuum assisted device. Even when using tips for success, patient cooperation is crucial for a successful biopsy. The patient must hold still after the abnormality has been identified and during the biopsy procedure. Patient comfort and patient positioning is of the utmost importance. Motion, if observed to the point of the abnormality no longer being visible, will require repositioning, increasing the dose to the patient. It can also result in having to take multiple biopsy passes, multiple skin incisions and can ultimately result in missed diagnosis (improper sampling). These potential issues make it ever the more important to carefully screen patients before the procedure, especially those with extreme arthritis or those with anxiety issues. Such patients may have major issues with holding still, which is detrimental as lesion localization and targeting depends on this. (4)
Selecting the proper patients for stereotactic biopsy is the first step to success, the second step (but the first in the biopsy room) is proper procedure preparation. Getting the preparation correct up front equates to less problems throughout the procedure. Manufacturers will have standard operating procedures (SOP’s) in their unit’s operation manual. These SOP’s should be strictly followed. One such example is the morning calibration and compression check. Also, the required checks and balances specific to needle selection just prior to biopsy, such as “zero-ing” the needle, assuring that you have positive stroke margin, and that all aspects of the computer are communicating properly as required by the manufacturer. If vacuum assisted devices are used, these will also need required preparation to function properly during biopsy. In addition, the biopsy tray should be prepared ahead of time; the lidocaine syringe and the biopsy needle should be prepared and ready for use. All of this allows the procedure to be completed as quickly as possible.
Positioning and Compression
To preface this section, it is imperative that all individuals working with stereotactic biopsy fully understand and are extremely knowledgeable in regards to their specific equipment. It is vital to the success of the procedure that the staff involved know the equipment, and most importantly, know how to troubleshoot the equipment when a problem arises.
Prior to bringing the patient in the room, the physician performing the biopsy and the assisting technologist should review the mammographic images to discuss the positioning approach as well as any other specifics of the individual case, such as allergies or physical limitations. The goal of proper stereotactic positioning is to identify the abnormality in the center (or close to the center) of the scout image and provide the shortest skin-to-abnormality distance for biopsy, as well as to have a positive stroke margin. In some cases, the abnormality will be too superficial for this; in these instances, a slight oblique is attempted to increase the depth. With the prone stereotactic unit, there is 360° access, which is invaluable to positioning. Figure 2 a-c demonstrates inadequate stroke margin and the ability to access the breast from the opposite side to achieve positive stroke margin.
Figure2a. Scout of mass in the CC position with a compression of 53.1. Click on image to enlarge
Figure2b. Compression is 53.1 and z is 45, opted to change approach to achieve stroke margin that is shorter. Click on image to enlarge
Figure 2c. The ability to move the c-arm with prone stereotactic table enables an approach in the CC position from below allowing for a positive stroke margin with a “z” of 44.5 with a compression of 65.2. Click on image to enlarge
The breast should be compressed to the point of tautness and the biopsy window should be filled. If this cannot be achieved with the breast, then additional filler should be used, such as play dough or aluminum foil.
The prone stereotactic table also utilizes a movable breast support; this should be adjusted per the breast thickness when compressed to allow for stereo shift. Figure 3 demonstrates what would be seen when the support is not appropriate for the breast thickness. In such an instance, as demonstrated in the example, the abnormality can still be visualized and the procedure can be performed without issue.
Figure 3. The large white area in the center demonstrates the visual effect that occurs when the breast support does not reflect the breast compression. In this instance the breast support was at 6, but should have been on 3. Click on image to enlarge
In rare instances, circumstances can lead to the lesion being lost on one of the stereo pair images because of stereo shift, which can be caused by positioning centering and breast support placement. (4) Additionally, blood vessels need to be avoided, to minimize complications during the procedure.
During the biopsy procedure, patients describe a wide range of discomfort, therefore pain control is important for patient comfort and for the success of the biopsy. Typically, subcutaneous administration of local anesthetic is all that is required, but it is also often administered to each side and deep to the abnormality to minimize discomfort from sample to sample. Amounts range, but up to 5 ml of 1or 2% lidocaine is used superficially, and up to 10 ml of 1 or 2% lidocaine with epinephrine is used for deeper anesthesia. (3) Lidocaine with epinephrine is usually not administered at the skin, due to the potential for damage. In some cases, lesion displacement, movement, and complete or partial obscuring can occur due to the administration of anesthesia. Figure 4a-b depicts a case in which the administration of lidocaine obscures the lesion of interest. Our protocol for local anesthesia calls for 3 ml of 2% lidocaine to the skin, 3 ml of 1% lidocaine with epinephrine for deep tissue, and an additional 3 ml of lidocaine attached to vacuum biopsy assembly device. As always the physician performing the biopsy should be aware of any allergies and adapt accordingly. The radiologist performing the procedure will have her protocol and the staff will prepare the anesthesia on the tray accordingly. We must keep in mind the patient is anxious and we want her as comfortable as possible to minimize any movement which will necessitate additional imaging and possibly additional re targeting which will lengthen the time on the table for the patient.
Figure 4a. Scout of subtle mass.Click on image to enlarge
Figure 4b. A stereo pre-fire images after lidocaine administration, the ability to see the mass is gone.Click on image to enlarge
Failure to Find the Abnormality
Most often, there is an identifiable landmark, such as a coarse calcification or nearby vessel, within the breast that assists with properly positioning an abnormality in the scout image. Every now and then, there will be a subtle finding that cannot be easily identified after multiple scout attempts. In cases such as this, it is best to get the patient back into the mammography room, estimate where to place the radiopaque marker based on prior imaging and position the patient in the planned approach for biopsy. Bring the patient back into the stereotactic core room and position the patient with the marker in the center of the biopsy window and re-scout as seen in Figure 5.
Figure 5 demonstrates the area of interest (subtle microcalcifications) with a radiopaque marker to aid in positioning in the core room.Click on image to enlarge
Subtle mammographic findings can often transfer over into the stereotactic room. In rare instances, the microcalcifications are too faint and are not detected with stereo imaging, and open surgical biopsy is recommended. Jeffries et al. reported on 20 needle localizations performed due to the inability to visualize faint calcifications for stereotactic core biopsy. Of the 20 biopsies; 4 were malignant (2 invasive ductal carcinoma (IDC), 1 intermediate grade ductal carcinoma in-situ (DCIS), and 1 low grade DCIS), 5 were atypical and 11 were benign. This study demonstrates the need for biopsy of these subtle calcifications as they found malignancy in 20% of the cases and malignancy or atypia in 45% of the cases. The authors also bring up valid points of the technical differences between digital mammography units and prone stereotactic units, such as reduced contrast because prone stereotactic units do not use a grid and that the compression during a stereotactic procedure is reduced. (5)
Stereotactic Biopsy Needle Device Selection
Typically, vacuum-assisted biopsy (VAB) needles are used for stereotactic biopsy. The advantages are numerous; the closed design, 360° biopsy rotation, suction of tissue into the biopsy troth, continuous suction of blood from the biopsy cavity, the rotating cutter, and the tissue collection basket. Additionally, there are lower upgrade rates, as the volume of tissue retrieved is larger, and sampling errors are minimized. A 2015 British study reports higher diagnostic accuracy and lower surgical upgrade rates when VAB is utilized in comparison to 14-gauge core needle biopsy for breast calcifications. (6,7) Additionally, positioning of the needle is not as critical. For example, needle placement ideally should be proximal and perfectly centered to the abnormality in the pre-fire position; for an abnormality utilizing a VAB needle, the needle can be positioned along any edge of the abnormality and successful sampling can be obtained, as the abnormality will be suctioned into the biopsy trough.
Accurate diagnosis with minimal invasion to the breast tissue is the goal with stereotactic core biopsy. Larger gauges and vacuum assisted devices have proven their accuracy rates as well as decreased upgrade rates, but Jackman et al. reported early on that the greatest improvements are demonstrated when 10 or more specimens are retrieved. (8) Facilities should consider this as sampling protocols are put in place. (8) A later study by Jackman et al. in 2001 reported on some of the factors that contribute to underestimation of ductal carcinoma in situ (DCIS). They looked at 373 14-gauge automated large core biopsies and 953 14- or 11-gauge directional vacuum-assisted biopsies at 16 institutions. This study evaluated biopsy device, probe size, lesion type and size, and number of core biopsy samples obtained per lesion. DCIS underestimations were 1.9 times more frequent with masses than with calcifications, 1.8 times more frequent with large-core biopsy than with vacuum-assisted biopsy, and 1.5 times more frequent with 10 or fewer specimens per lesion than with more than 10 specimens per lesion. (9)
Tissue Marker Placement
Following completion of the biopsy, a tissue marker should be placed at the biopsy site. This is becoming the standard of care after all breast biopsy procedures. The ACR committee on stereotactic parameters recommends placing a tissue marker after biopsy when; the area is difficult to see after biopsy, the area is completely removed after biopsy, when proof of proper lesion biopsy is needed, or if pre-surgical chemotherapy is planned. (10) The committee also recommends that a post procedure mammogram (2 orthogonal views) should be performed to document the tissue marker placement and the radiology report should state the position of the marker in relation to the biopsy site/lesion. It is very important to document clip placement as they can migrate. Rosen, in 2001, reported on 111 cases with a clip deployment; in most the cases (56%) the clip was within 5 mm of the target on post biopsy imaging (mediolateral and craniocaudal), in 16% the clip within 6-10 mm on one projection of the post biopsy images, and in 28% of the cases the clips were more than 1 cm away from the target on at least one of the post biopsy images. When looking at the cancers only (39 out of the 111), the clips were at least 1 cm away on at least 1 projection in 46% of the cases. The authors concluded that clip placement varies and should always be documented by post biopsy/clip placement imaging in 2 orthogonal views for documentation. (11) Sites should have a protocol in place if the tissue marker is too far from the biopsied lesion, for example, if final clip placement is in another quadrant. In these instances, it may be necessary to deploy another clip. Essserman et al. describes some of the reasons for clip migration after vacuum-assisted biopsy in a 2004 Radiographics article. The article demonstrates many migration scenarios, such as the accordion effect (clip migration with the release of breast compression), simple migration in fatty tissue, migration due to bleeding (the clip can migrate with bleeding and in can travel out of the breast if not attached to breast tissue), and clip floating in a hematoma if not attached to breast tissue. It is important to be aware that the potential for migration increases when these situations are observed. (12)
Post Biopsy Care
To minimize the complications of a hematoma, staff should apply pressure/compression to the biopsy area until hemostasis is achieved, which is approximately 10 minutes. Aftercare instructions for the wound and pain management, as well as emergency instruction should be gone over with the patient as well as provided in written form.
Facility protocols should be in place for biopsy results. Some facilities call the patients on all biopsy results, while others call on atypical results and cancer results only. Whatever the result is being discussed, the radiologist/physician needs to convey the results in a manner that the patient can understand. If benign results, the physician should be reassuring and discuss the recommended follow-up. If atypical results, the physician may be recommending open surgical biopsy and should discuss the steps involved to get that process going, such as, contacting her referring physician, choosing a breast surgeon, and picking up her images and reports. Conveying that the biopsy result is cancer is very important and should be done by the radiologist that performed the procedure. The physician discusses the results and answers questions the patient may have regarding the next step. Every facility or department may have different protocols for how the results are given whether over the phone or in-person. Patient advocates may be available to facilitate supporting the patient if they have additional questions after the diagnosis is given. It is very important to discuss the options of pre-surgical breast MRI and reassuring the patient that you will be there for them if they need anything at all.
Importance of tracking outcomes and follow-up
Tracking your biopsy outcomes is mandatory for the MQSA and Food and Drug Administration (FDA) yearly audit. The specifics required for MQSA were discussed previously in the accreditation section. Aside from the requirements, pathological and imaging concordance is necessary for accurate follow-up of patients as well as a successful stereotactic program. This tracking will allow physicians to determine the next recommendation to the patient; benign 6 month versus one year follow-up to confirm stability, discordant-re-biopsy with core or recommendation for open surgical biopsy, high risk or atypical-recommend open surgical biopsy, malignant-recommend surgical consultation and treatment. In instances where microcalcifications were biopsied and confirmed by specimen radiograph, but the pathology report fails to describe them, a request for additional cuts by the pathologist should be made for final diagnosis. Facilities should have their recommendations for each scenario strictly in place for follow-up after core biopsy. The radiologist that performed the needle core biopsy needs to review the biopsy results and dictate a final recommendation especially if the original radiology report deferred to the core biopsy result before a final recommendation was given. If the radiologist has a strong index of suspicion for the lesion but the biopsy results are benign, a review of the case is imperative by the doctor that performed the procedure for the correct recommendation to be given to the patient and her referring physician.
Johnson et al. researched breast cancer detection rates and stages in those with short interval follow-up (3-8 months after biopsy) compared to those that were returned to yearly screening (9-18 months after biopsy) after benign stereotactic or ultrasound guided results. They found similar results in both groups; 2.5 cancer per 1000 with an invasive rate of 1.5/1000 with 25% having late stage disease in those with short interval follow-up (27 ipsilateral cancers in 10,715 examinations) and 2.3 cancers per 1000 with an invasive rate of 1.7/1000 with 27% (16 ipsilateral cancers in 6,916 examinations) having late stage disease in those that returned to annual screening mammography after benign biopsy. Their findings suggest that those patients with radiologic-pathologic concordant benign lesions diagnosed at stereotactic or US guided needle core biopsy could return to yearly screening. (13) An earlier article published in 2010 by Salkowski et al., followed 1,057 benign and concordant lesions. They reported no cancers found at 6 or 12 month follow up and the re-biopsy rates were below 1% in both follow-up groups, concluding that 6-month follow-up did not contribute to improved breast cancer diagnosis. (14) A similar study by Adams et al. demonstrated similar results when looking at their institutional protocol of 6 month, 1-year and 2-year follow-up after concordant benign biopsy. There was no cancer was found at 6 month and 1 year, 5 cancers were found at 2 years; 2 contralateral and 3 ipsilateral cancers. These authors also concluded that there was no benefit to cancer detection with short interval follow-up of concordant benign lesions. (15)
Recommendations for high risk and atypical lesions diagnosed at needle core biopsy remains a controversial subject. A recent article in Modern Pathology from David Geffen School of Medicine at UCLA looked at 462 high risk lesions; 249 atypical duct hyperplasia, 72 flat epithelial atypia, 50 atypical lobular hyperplasia, 37 lobular carcinoma in-situ, and 54 radial scar cases. Three hundred and thirty- three (72%) went on to open surgical biopsy. The researchers found an upgrade rate to ductal carcinoma in-situ (DCIS), pleomorphic carcinoma in situ, or invasive mammary carcinoma (IMC) of 18% for atypical duct hyperplasia, 11% for flat epithelial atypia, 9% for atypical lobular hyperplasia, 28% for lobular carcinoma in-situ, and 16% for radial scar. They concluded that careful radiological and pathological correlation is needed to identify the high-risk lesions that may not need excision. (16) This paper also reiterates that high-risk lesions found at core biopsy are not only markers for future cancer, but most importantly, an indicator that a carcinoma was missed due to biopsy sampling, driving home the importance of radiological/pathological concordance. Similarly, a study out of New York University Langone School of Medicine reported on the frequency of discordant lesions and false negative cancers at stereotactic VAB. The authors looked at 1861 stereotactic VABs over a seven-year time frame. All VABs were performed with either a 9 or 11-gauge needle and between 10 - 12 specimens were obtained. They found 23 discordant cases, of which 7 were found to be cancer; 3 IDC and 4 DCIS from six calcification cases and 1 architectural distortion case. They found no significant difference between needle gauges. These authors too emphasize the need for careful radiologic pathologic review after stereotactic VAB core biopsy. (17) After their careful review, they found that; needle placement was off in 3 cases, specimen imaging showed a small amount of calcium in 5 cases, non-diagnostic sampling occurred in 5 cases, and discordant findings in 10 cases.
The stereotactic core biopsy technology has become an essential part of breast disease diagnosis. A well-educated and experienced biopsy team is key to a successful program, as this biopsy method continues to be invaluable for microcalcifications, subtle masses and architectural distortions.
The author would like to thank her stereotactic core biopsy technologists Cathy Case, Kathy Barnsdale, and Jill Dale and her research coordinators Renee Morgan and Andrea Arieno for their contribution to this CME.
- Silverstein HM, ZRecht A, Lagios MD,
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