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Massachusetts General Hospital
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Volume 4 Issue 9 - September 2006
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Percutaneous Image-Guided Breast Biopsy
 
  • Image-guided biopsy is indicated for both palpable and non-palpable breast lesions suspicious for malignancy and is a cost-effective procedure that reduces the number of surgeries

  • Ultrasound-guided biopsy allows real-time imaging, can be performed without breast compression, and is the preferred method if the lesion is detectable with ultrasound

  • Stereotactic (mammographic) biopsy is used primarily for microcalcifications and for masses not visible with ultrasound

  • MRI-guided biopsy is used for suspicious areas of contrast enhancement that cannot be seen on ultrasound or mammography


Ultrasound-Guided Biopsy
Stereotactic (Mammographic) Biopsy
MRI-Guided Biopsy
Histological Concordance
Scheduling and Patient Management
Further Information
References

P
ercutaneous image-guided breast biopsies are rapid, minimally invasive procedures that make surgery unnecessary for a large majority (70-80%) of patients whose lesions will prove to be benign. The image-guided biopsies are performed under local anesthetic with no need for conscious sedation using a small incision that requires no stitches to close. The procedures do not deform the breast and cause minimal to no scarring on subsequent mammograms. Complications, such as hematoma and infection are rare, occurring in less than 1 per 1000. Patients diagnosed with breast cancer by image-guided biopsy will require fewer surgeries, on average, than those diagnosed by surgical biopsy. Thus, percutaneous image-guided breast biopsies are both medically preferable and cost-effective and have largely replaced surgical biopsies for pathologic diagnosis.

Image-guided biopsy is recommended for almost all cases of suspected breast cancer (BI-RADS 4-5), whether or not the patient is symptomatic or the lesion palpable.

 
Women who have palpable lesions not visible by imaging are biopsied surgically. Because percutaneous biopsy requires that the patient have normal coagulation rates, surgical biopsy may be considered in patients taking coumadin to minimize their time off medication.

Even if imaging prior to intervention shows a very high likelihood of malignancy, image-guided biopsy can provide useful information for surgical planning. In addition to confirming the diagnosis, biopsy can sometimes reveal multifocal (multiple sites within same quadrant) or multicentric (multiple sites within different quadrants) carcinoma. Knowing that the lesion is definitively a cancer allows the surgeon to sample axillary nodes for metastasis at the time of definitive excision. In addition, the likelihood of attaining clear margins at the first operation after percutaneous diagnosis of cancer is 75-100%, compared to 45-64% when a diagnosis has not been established, thereby sparing additional surgery in a significant number of patients.

Percutaneous image-guided biopsy may be performed under ultrasound, stereotactic, or MRI guidance. The selection of modality depends on the imaging characteristics of the lesion. Some advantages and disadvantages of the alternate procedures are listed in Table 1.


Table 1. Advantages and Disadvantages of Percutaneous Breast Biopsy Methods
Biopsy Method
Advantages Disadvantages
Ultrasound-guided Real-time visualization of biopsy needle

Accessibility of all areas of breast and axilla

Multidirectional sampling possible

Low cost

Can only be performed if lesion is sonographically evident

Difficulty in confirming lesion retrieval

Stereotactic

Can be used for almost all lesions visualized on mammograms

X-ray of biopsy specimen confirms that targeted lesion was sampled

No real-time visualization of biopsy needle

Discomfort from breast compression

Must have arms raised up; may not be possible for patients with limited shoulder movement

Must have adequate compressed breast thickness to allow biopsy

MRI-guided Can be performed when lesions are visible on MRI but not on other modalities.

Transient contrast enhancement may limit ability to see lesion

Difficult to confirm lesion retrieval



Figure 1. Ultrasound-guided biopsy of breast lesion. The diagnostic study (A) shows a solid lesion (calipers) suspicious for cancer.  An image during the biopsy (B) shows the core biopsy needle (arrows) sampling the lesion.


Ultrasound-Guided Biopsy
   
Ultrasound guidance is the method of choice for all patients when the lesion can be visualized by this modality (Figure 1). This method is easiest for both patient and operator because, unlike the other techniques, the lesion can be can be sampled without breast compression while the patient is reclining in the supine position. Under real-time imaging guidance, a radiologist inserts a core biopsy needle into the lesion and withdraws multiple samples. The sensitivity and specificity of this procedure for detecting malignancy has been reported to be 97% and 100%, respectively.

  A radiographically visible clip, 1-2 mm in size, is sometimes placed after the biopsy sample is removed to mark the site from which the sample was taken in case further surgery is needed. Placement of a clip is considered if the targeted lesion is <5 mm in size, because the lesion remaining after biopsy may be too small to find by ultrasound. A clip will also be placed if the patient is a likely candidate for neoadjuvant therapy; that is if a lesion is ≥3 cm and the imaging characteristics are highly suggestive of malignancy. In these cases, chemotherapy may cause the tumor regression to the point where it is no longer evident on imaging. The presence of a clip allows accurate localization of the tumor at the time of surgical excision.


*MRI screening is only for patients with high familial risk factors. See When should breast MRI be used?
Radiology Rounds, October 2005
Figure 2. Algorithm for the selection of the appropriate image-guided biopsy modality.


Stereotactic (Mammographic) Biopsy
  MRI-Guided Biopsy
Mammographic calcifications, a potential sign of malignancy, are generally not visible by ultrasound; for these lesions stereotactic biopsy is the method of choice. For this procedure, the patient must lie prone on a special table, which is elevated to allow access to the breast from below. The breast is held in compression while stereotactic x-ray images are taken, the 3-dimensional location of the lesion determined, and the optimal path to the lesion calculated. A computer-guided needle is inserted to the calculated position and a second pair of stereotactic images confirms the position of the needle. Once the lesion has been biopsied, radiographic demonstration of the originally targeted lesion in the specimen confirms sampling validity. If the target lesion is not present, the procedure can be repeated. In the vast majority of cases, marker clips are placed immediately after biopsy because the lesion may no longer be visible radiographically. The sensitivity and specificity of stereotactic biopsy for detecting malignancy has been reported to be 95% and 97%, respectively.

  MRI-guided biopsy is only used when suspicious lesions can be visualized with this modality but not with mammography or ultrasound. The patient lies prone with her breasts positioned in a dedicated breast MRI coil and stabilized with moderate compression in a biopsy guidance grid. After a localizing scan, the patient table is moved out of the bore of the magnet to allow access to the breast. A biopsy sheath is inserted into the calculated position of the lesion and a second scan confirms the correct position of the sheath. The table is again moved out of the magnet bore and a biopsy sample withdrawn with a vacuum assisted device and an MRI-safe marker clip placed to denote the site of biopsy should surgery be needed. A final scan of the biopsied region verifies the location of the sampling site and marker clip. Reports of the technical success rate range from 95-100%.The reported cancer yield is 20-55% in the population who undergo this procedure.
Figure 3.  MRI-guided biopsy. The diagnostic MR image (A) demonstrates an area of abnormal contrast enhancement (arrow).  Mammogram following the biopsy (B) shows the clips (arrows) placed to mark the biopsy site.



Histological Concordance
Image-guided biopsies are not considered complete until the result from histological analysis is shown to be in agreement with the suspected radiologic diagnosis. This process is known as establishing radiologic-pathologic concordance. If the histological results do not agree with the radiologic assessment (discordance), the lesion must be surgically excised for pathologic certainty. In addition, if there are findings of atypical ductal hyperplasia, lesion resection is warranted because surgical findings may upgrade the lesion to ductal carcinoma in situ or invasive carcinoma.


Scheduling and Patient Management
Once identified as a candidate for percutaneous image-guided biopsy, the patient meets with the Breast Imaging Nurse Coordinator, who will explain the details of the upcoming procedure, answer the patient’s questions, and coordinate a time for her biopsy. Alternatively, breast biopsy procedures can be scheduled by calling 617-726-3094.

 

Further Information
For further questions on percutaneous breast biopsy, please contact Elizabeth Rafferty, MD , Acting Director of Breast Imaging, at 617-726-3093.

We would like to thank Dr. Rafferty and Michelle C. Specht, M.D., Surgical Oncology, for their advice and assistance in the preparation of this article.







This article provided useful information about the appropriate use of imaging studies:



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References
   

Fajardo, L, Pisano, E, Caudry, D, Gatsonis, C, Berg, W, Connolly, J, Schnitt, S, Page, D, McNeil, B and Radiologist Investigators of the Radiologic Diagnostic Oncology Group V. (2004) Stereotactic and sonographic large-core biopsy of nonpalpable breast lesions: results of the Radiologic Diagnostic Oncology Group V study. Acad Radiol 11: 293-308

Liberman, L. (2002) Percutaneous image-guided core breast biopsy. Radiol Clin North Am 40: 483-500

Nurko, J and Edwards, MJ. (2005) Image-guided breast surgery. Am J Surg 190: 221-7

Perlet, C, Heywang-Kobrunner, SH, Heinig, A, Sittek, H, Casselman, J, Anderson, I and Taourel, P. (2006) Magnetic resonance-guided, vacuum-assisted breast biopsy: results from a European multicenter study of 538 lesions. Cancer 106: 982-90

Simon, JR, Kalbhen, CL, Cooper, RA and Flisak, ME. (2000) Accuracy and complication rates of US-guided vacuum-assisted core breast. Radiology 215: 694-7

Verkooijen, HM. (2002) Diagnostic accuracy of stereotactic large-core needle biopsy for nonpalpable breast disease: results of a multicenter prospective study with 95% surgical confirmation. Int J Cancer 99: 853-9