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IMAGE-GUIDED BREAST BIOPSY: THE ABBI* SYSTEM by William E. Kelley, M.D. 
Stereotactic core needle biopsy is one procedure for
tissue diagnosis of a nonpalpable breast lesion presenting as a suspicious
finding on mammography. Ultrasound-guided needle biopsy is a cost effective
alternative, but is more operator-dependent, with a reported accuracy of
47-91%. Stereotactic core biopsy is minimally invasive, requiring only a
4mm incision, and is safe. It has a reported accuracy of 98% in experienced
hands, which equals the results of surgical series. |
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Stereotactic core needle biopsy (SCNB) has several drawbacks, however. Many
women are not satisfied with a needle biopsy. The histologic analysis of
needle biopsy has limitations. When atypical ductal hyperplasia is diagnosed
by core needle biopsy, excisional biopsy is mandated since there is a 50%
incidence of cancer in those lesions. Core needle biopsy pathology must
be carefully correlated with the mammography findings and a larger tissue
biopsy is indicated when discordant results are found, since up to 50% of
these cases will prove to be malignant. Three recent studies from John Hopkins,
Memorial Sloan-Kettering, and Yale University have independently identified
that 18-19% of patients will require a second diagnostic procedure following
SCNB (1-3). In Dershaw's review of 314 SCNB's at Sloan-Kettering, 44% of
the patients who underwent second biopsies were found to have cancer.
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Stereotactic Technology
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When cancer is diagnosed by core needle biopsy, the degree of intraductal
component, precise nuclear grade, and potential for obtaining a tumor-free
margin by excision cannot be accurately assessed. The patient's prognosis
can only be guessed, and any discussion of therapeutic options must be tentative
and presented in general terms. Lumpectomy may be planned, but the potential
for achieving a tumor-free margin is unclear. | |
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United States Surgical Corporation has developed a new technology which
permits sampling of a mammographic lesion while preserving the histologic
architecture for complete, traditional pathologic analysis. The Advanced
Breast Biopsy Instrumentation, or ABBI* System utilizes the same stereotactic
guidance system as core needle biopsy. The ABBI* system was developed in conjunction with
Lorad, a Division of ThermoTrex Medical Corporation.
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On-line video of the ABBI* procedure. |
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The patient is positioned on the table. The ABBI* table provides 360
degrees access to the breast providing the shortest distance between skin
and targeted tissue helping to avoid unaffected quadrants. Additionally,
an inferior approach is possible. |
ABBI* Table
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The patient's breast is compressed. |
Compress Breast
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Stereotactic x-rays are taken allowing the physician to visualize and target the non-palpable lesion's location to within 1mm of accuracy. |
Stereotactic X-rays
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A localizing needle is guided to the precise location of the lesion by digital stereotactic X-rays through an incision. |
Localizing Needle
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The position of the needle is verified by digital stereotactic X-rays, and a T-fastener is then deployed, thus fixing the lesion in place. The position of the T-fastener is then confirmed with another stereotactic X-ray, completing the localization sequence. |
T-fastener
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The biopsy sequence begins with further infiltration of local anesthesia, and the incision is extended to a length 3 mm longer than the diameter of the biopsy cannula. If the lesion is deep in the breast, the physician undermines the superficial tissues with scalpel dissection to reduce the size of the ultimate specimen. A cylindrical cannula is then advanced over the needle and T-fastener while a motorized, oscillating, circular cutting blade incises the breast tissue. |
Biopsy Sequence
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The cannula is advanced beyond the lesion to a predetermined depth, and another stereotactic X-ray is taken to confirm that a sample has been captured within the cannula. At every step, the precise location of the device and the lesion are verified by digital X-rays. |
Cannula Sample
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A cautery snare then cuts across the deep end of the cannula, completing the biopsy, and the cannula and specimen are removed. |
Cautery Snare
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When the specimen has been removed, a completion mammogram is taken before the patient is taken out of compression. |
Digital X-rays
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A specimen X-ray is performed to confirm that the targeted tissue is contained within the sample. |
Specimen X-ray
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The patient is then rolled supine and the biopsy site is inspected. The deep portion of the biopsy is marked with a clip under direct vision. Bleeding is an infrequent problem and is easily controlled with cautery or clips or sutures. There are four cannula sizes available: 5, 10, 15 and 20 mm. 
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The smallest ABBI* unit removes a specimen smaller than a pencil eraser and the largest unit removes a specimen the size of half a wine bottle cork. The pathologist makes cross sections, converting the specimen into a "stack of coins." The architecture of the lesion is seen in cross section. The physician chooses the cannula size consistent with the size of the sample desired. |
Pathology Specimen
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Our initial experience with 125 ABBI* procedure biopsies has been very positive.
Specimen X-rays have confirmed the sample
to be from the targeted tissue, and the pathology has corresponded with
the X-ray findings in all cases. Bleeding has not been a problem. Cautery
has been used less than half of the time and a suture or clip has been needed
in only four cases. There has been only one complication, a small ecchymosis.
There have been no hematomas and no wound infections. Only one patient has
required a prescription analgesic, and all patients have returned to work
or to their normal activities the following day. No second diagnostic procedures
have been needed.
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The ABBI* procedure is very cost effective. It is much less expensive
than open wire localization biopsy in the operating room. The ABBI* biopsy
does not require an O. R. and is usually performed in the same room as stereotactic
core needle biopsy. When the total costs of core biopsy are considered,
the ABBI* biopsy may very well prove to be less expensive than a needle
biopsy. Routine unilateral follow-up mammograms are required after all SCNB's
at six months, and often at eighteen months. Early follow-up mammography
after ABBI* biopsy is ordered selectively and infrequently, comparable to
open biopsy, thus saving X-ray costs. Furthermore, if 18-19% of core biopsies
require a second diagnostic procedure, as suggested by the Hopkins, Memorial,
and Yale studies, the total cost of core biopsy exceeds the cost of ABBI*
biopsy.
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ABBI* procedure: no second diagnostic procedures have been needed. |
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The physician and patient have multiple options for tissue diagnosis of a mammogram finding. Image-guided, minimally invasive biopsies have both cosmetic and economic advantages. The size of the incision is predictable for each cannula and heals remarkably well, probably due to the atraumatic nature of the procedure, lack of tissue damage from retractors, and absence of talc contamination. Core biopsy incisions are smaller, measuring 4 mm as compared with 8, 13, 18, or 23 mm for the ABBI* biopsies. Most ABBI* patients have the security of knowing that the targeted tissue is no longer seen on X-ray, which is a very important issue for some women. For other women, the 4 mm incision is a more important factor and they are willing to accept an 18% rebiopsy rate and the need to follow their residual mammographic lesion closely. The patient who receives a malignant diagnosis following ABBI* biopsy can usually be informed of her prognosis and can hear a full and weighted discussion of her therapeutic options, since the physician has the advantage of full and detailed pathologic examination. After a lengthy discussion of the advantages and disadvantages of the image-guided biopsy options, the patient can make an informed decision and choose the best option for her. On a final note, it must be emphasized that the ABBI* biopsy is a diagnostic procedure. Randomized prospective studies will be needed with long term follow-up results before the ABBI* procedure can be performed as a therapeutic procedure.
BIBLIOGRAPHY
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