DOI:10.2214/AJR.07.2658
AJR 2008; 191:1216-1219
© American Roentgen Ray Society
Sonographically Guided Marker Placement for Confirmation of Removal of Mammographically Occult Lesions After Localization
Cecilia L. Mercado1,
Amber A. Guth2,
Hildegard K. Toth1,
Linda Moy1,
Deborah Axelrod2 and
Joan Cangiarella3
1 Department of Radiology, New York University School of Medicine, New York
University Cancer Institute, 160 E 34th St., 3rd Fl., New York, NY
10016.
2 Department of Surgery, New York University School of Medicine, New York,
NY.
3 Department of Pathology, New York University School of Medicine, New York,
NY.
Received June 1, 2007;
accepted after revision September 9, 2007.
Address correspondence to C. L. Mercado
(cecilia.mercado{at}med.nyu.edu).
Abstract
OBJECTIVE. We evaluated the benefit of placing a marker under
sonographic guidance at the time of localization to aid in identifying
mammographically occult lesions within the specimen at the time of surgical
excision and to evaluate margin status.
MATERIALS AND METHODS. We reviewed 135 sonographically guided needle
localizations performed on mammographically occult lesions. Imaging during the
localization procedure, marker placement, and specimen radiographs were
reviewed, and the findings were correlated with the histopathologic
findings.
RESULTS. Of the 135 mammographically occult lesions, 77 were
localized without marker placement and 58 with marker placement. The 58
localizations with marker placement were for masses with a mean lesion size of
9 mm. Specimen radiography of these lesions showed a marker within the
specimen in 56 cases (97%) and visualization of the lesion in only seven cases
(12%). Specimen radiography of localizations without marker placement showed
visualization of the lesion in 18 cases (23%). Of the 11 malignant lesions
(19%) localized with marker placement, none had a positive inked margin, but
five (46%) had close margins necessitating reexcision. Of the 26 malignant
lesions (34%) localized without marker placement, two (8%) had a positive
inked margin, and eight (31%) had close margins necessitating reexcision.
CONCLUSION. At needle localization of breast lesions, marker
placement under sonographic guidance is beneficial because it enables
immediate confirmation of accurate surgical removal of the localized lesion at
surgical excision. Use of marker placement, however, does not reduce the
percentage of cases with close margins necessitating reexcision.
Keywords: breast • breast specimen • mammography • sonography
Introduction
Sonography is commonly used for characterization of breast masses, for
guidance of diagnostic procedures such as aspiration and core biopsies, and
for preoperative needle localization
[1,
2]. Procedures performed with
sonographic guidance are more advantageous owing to lack of ionizing radiation
and breast compression, increasing safety, patient comfort, and ease and speed
of performance [3,
4]. Sonography is especially
useful for needle localization of lesions not visualized with mammography.
Specimen radiography or specimen sonography can be used to confirm surgical
removal of lesions that have been localized with sonographic guidance
[5,
6]. In instances in which
specimen sonography is not feasible, confirmation of surgical removal is
solely dependent on specimen radiography. If the lesion is not visible with
mammography, assurance of surgical removal can be difficult.
The introduction of sonographically placed breast markers facilitates
radiographic identification of the location of mammographically occult
lesions. Breast markers are commonly used after breast biopsy when complete
obliteration of a lesion is suspected owing to small lesion size or before
neoadjuvant chemotherapy for verification of the site of breast cancer after
treatment [7,
8]. However, breast markers are
not always placed after all sonographically guided diagnostic procedures. We
sought to evaluate the benefit of placing a breast marker under sonographic
guidance at needle localization to aid in identifying mammographically occult
lesions within the specimen at surgical excision and to evaluate margin
status.
Materials and Methods
Study Group
Six hundred twenty-eight consecutive needle localizations during the
21-month period September 1, 2004, to June 30, 2006, were retrospectively
reviewed. Needle localizations were performed by one of six radiologists
specializing in breast imaging, and surgical excisions were performed by one
of six breast surgeons. Of the 628 needle localizations, 301 (48%) were
performed under sonographic guidance, and 157 of those (25% of the 628)
revealed mammographically occult lesions. Twenty-one of the 157 procedures
were excluded because of the presence of a marker at the biopsy site placed
during previous percutaneous biopsy, and one was excluded because of lack of
availability of specimen radiography. The other 135 procedures (21% of the
original 628) constitute the basis of this study. This retrospective study was
approved by the institutional review board. The 135 procedures were performed
on 123 women (mean age, 48 years; range, 25–86 years). In all cases, the
lesions localized were sonographically visualized. The procedures were divided
into two groups: those in which a marker was placed during the needle
localization procedure and those in which a marker was not placed.
Imaging
The mammographic and sonographic images obtained during the needle
localization and marker placement procedures were retrospectively reviewed for
evaluation of lesion type, lesion size, and appropriate wire and marker
placement. The distance between the localizing wire and the marker was
ascertained from postprocedure mammograms. In all cases, specimen radiographs
were retrospectively reviewed for visualization of the targeted lesion and for
wire and localizing markers if placed.
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Fig. 1A —46-year-old woman without symptoms. Sonogram of left breast
shows oval hypoechoic solid mass with circumscribed margins and without
posterior acoustic enhancement or shadowing. Cytologic examination of specimen
from sonographically guided fine-needle aspiration revealed atypical
cells.
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Fig. 1C —46-year-old woman without symptoms. Sonogram of left breast
obtained during placement of localizing marker shows collagen plug with
embedded marker (arrow) visible as linear structure of increased
echogenicity within lesion.
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Fig. 1D —46-year-old woman without symptoms. Left mediolateral oblique
mammogram obtained after sonographically guided needle localization and marker
placement procedures shows localizing marker (arrow) adjacent to
localizing wire. Mass is mammographically occult and not visible.
Retroglandular saline implant is evident.
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Fig. 1E —46-year-old woman without symptoms. Specimen radiograph shows
localizing marker (arrow) within specimen adjacent to localizing
wire. Localized lesion is not well depicted. Marker is used to confirm
surgical removal of lesion. Histopathologic finding was tubular adenoma.
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Needle Localization and Clip Placement Procedures
Sonographically guided preoperative needle localization was performed with
a 21-gauge modified Kopans spring-hook localization needle inserted into and
through the lesion under sono graphic guidance with a freehand technique. The
hookwire was then inserted through the needle, and the needle was removed. In
cases in which a breast marker was placed after needle localization, a
14-gauge introducer and sonographic guidance were used to place a localizing
clip embedded in a bioresorbable col lagen plug (Cormark, Ethicon
Endo-Surgery) into or adjacent to the lesion. Marker placement was per formed
on some lesions according to surgeon preference. Postprocedure craniocaudal
and 90° mediolateral mammograms were obtained to ensure proper placement
of the wire and marker (Fig.
1A,
1B,
1C,
1D,
1E). Radiographs (Faxitron
unit, Faxitron X-Ray Corporation) of the surgical specimen were obtained to
confirm surgical removal of the lesion or marker at the surgical
procedure.
Pathologic Evaluation
The histopathologic findings on the surgical specimens were reviewed by a
pathologist with expertise in breast pathology and were correlated with the
imaging findings. In all malignant cases, the proximity to the inked margins
was assessed microscopically for evaluation of the surgical margins. The
specimens were grouped into three categories depending on whether the margins
were positive (lesion at inked margin), close (1–4 mm from the margin),
or negative (5 mm or more from the margin).
Statistical Analysis
The cases with and without marker placement were compared with respect to
each proportion shown in Table
1. The Mann-Whitney test was used for patient age and lesion size,
and Fisher's exact test was used for specimen radiography, histologic finding,
and margins. Each reported p value was two-sided and not subjected to
multiple comparison correction.
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TABLE 1: Findings at Specimen Radiography and Histopathology for Needle
Localizations With and Without Marker Placement
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Results
Study Population and Lesions
The 58 localizations with marker placement were performed on 56 women (mean
age, 47 years; range, 29–73 years). The mean lesion size was 9 mm
(range, 2–21 mm). The 77 localizations without marker placement were
performed on 67 women (mean age, 49 years; range, 25–86 years). The mean
lesion size was 10.5 mm (range, 3–40 mm). The mean patient age and mean
lesion size for both groups of needle localizations with and without marker
placement were similar (Table
1). Eighty of the 135 lesions (59%) had been subjected to
sonographically guided fine-needle aspiration or core needle biopsy before
surgical removal. In the 77 needle localizations without marker placement, 28
lesions had been subjected to sonographically guided fine-needle aspiration
and 16 lesions, to sonographically guided core needle biopsy. Among the 58
needle localizations with marker placement, 24 lesions had been subjected to
sonographically guided fine-needle aspiration and 12 lesions, to
sonographically guided core needle biopsy.
In all cases postprocedure mammograms showed appropriate marker deployment
in the specific quadrant of the breast near the localizing wire. Because the
exact distance between the mammographically occult lesions and the markers
could not be ascertained on the postprocedure mammograms, the distances
between the localizing wires and the markers were measured; the mean distance
was 0.3 cm (range, 0–1.1 cm). There were no complications of the marker
placement procedure.
Specimen Radiography
Specimen radiography of needle localizations with marker placement showed a
marker within the specimen in 56 cases (97%) and visualization of the lesion
in only seven cases (12%). In the two cases (3%) in which a marker was not
identified in the specimen, follow-up mammography did not depict the marker
within the breast, confirming marker removal during the surgical procedure.
Conversely, specimen radiography of localizations without marker placement
depicted the lesion in 18 cases (23%). The percentage of cases in which lesion
or marker removal was confirmed at surgery was significantly higher in the
cases in which a marker had been placed during the procedure (97%) than in
cases in which a marker was not placed (23%). The findings at specimen
radiography and histopathologic examination for the two groups are summarized
in Table 1.
Specimen Histopathology
Histopathologic examination of the excised specimens revealed 47 of the 58
lesions (81%) localized with marker placement were benign, as were 51 of 77
lesions (66%) localized without marker placement. In the cases of all benign
lesions, either a discrete finding or a healing biopsy site (when no discrete
finding was present) was identified. Malignant lesions were identified in 19%
of cases with marker placement and in 34% of cases without marker placement
(Table 1).
None of the 11 malignant lesions localized with a marker had a positive
inked surgical margin, in contrast to the 26 malignant lesions localized
without a marker, two (8%) of which had a positive inked surgical margin
(Table 1). The percentage of
cases with close margins was similar for the two groups: 46% with marker
placement and 31% without marker placement.
Table 2 shows the margin
status of the various histopathologic subtypes of the malignant lesions
localized with and without marker placement. In both the group with and the
group without marker placement, six of the seven ductal carcinomas in situ
(86%) and three of the six invasive lobular carcinomas (50%) had close or
positive inked margins that necessitated reexcision. Only five of the 20
invasive ductal carcinomas (25%) and one of the four invasive carcinomas with
ductal carcinoma in situ (25%) were found to have close or positive inked
margins. However, the overall study sample size for malignant lesions was
small, and these findings are not statistically significant. In addition, no
significant difference in frequency of positive or close margins within the
two groups was found among the histopathologic subtypes encountered at
surgical excision (Table
2).
Discussion
Specimen radiography or specimen sonography is performed after needle
localization procedures to confirm surgical removal of the localized lesion.
Specimen sonography is the preferred examination for surgical specimens
initially localized with sonographic guidance
[6]. However, in instances in
which specimen sonography is not feasible, specimen radiography can be
performed. The lack of proximity of the breast imaging center to the operating
room can make specimen sonography logistically difficult if not impossible. In
many instances, the lesion localized can be visualized with both mammography
and sonography, and therefore specimen radiography can be performed to confirm
surgical removal. However, it becomes difficult when the lesion being
localized is not readily visualized with mammography; in those instances,
specimen radiography probably will not be helpful.
We evaluated the benefit of placing a marker under sonographic guidance at
needle localization to aid in identifying mammographically occult lesions
within the specimen at surgical removal. As in our study, mammographically
occult lesions can sometimes be visualized with specimen radiography, probably
because of the decrease in tissue surrounding a lesion in specimens. In our
study, only 18.5% of all mammographically occult lesions (25 of 135) were seen
on specimen radiographs. In more than 80% of all cases, the specimen
radiographs from needle localizations of these mammographically occult lesions
did not confirm surgical removal of the lesions at surgery. The need for a
technique that facilitated confirmation of appropriate surgical excision of
these mammographically occult lesions became apparent. Placing a radiopaque
marker at the site of the lesion under sonographic guidance at needle
localization enables visualization of the localized site with specimen
radiography when specimen sonography is not available.
In our study, confirmation of lesion or marker removal with specimen
radiography was achieved at surgery 97% of the time when a marker was placed
at needle localization versus 23% of the time when a marker was not placed.
These results are similar to a reported 95.4% rate of lesion visualization
achieved with specimen sonography
[6]. Thus our findings show
marker placement with specimen radiography for localization of
mammographically occult lesions is a useful technique for confirmation of
surgical removal of a lesion.
Improvement in margin status in cases of malignant lesions was achieved
with a sonographic marker placement procedure. Clear inked margins were found
in all cases in which a marker was placed, in contrast to 92% of cases in
which a marker was not placed. However, there was no significant difference in
the percentage of cases with positive or close margins necessitating
reexcision. No differences in margin status were seen among the various
histopathologic subtypes of malignant lesions localized with or without marker
placement.
There are limitations to the sonographically guided marker placement
procedure. Appropriate placement of the marker is important and must be at the
exact site of the localized lesion. The procedure is typically easy and quick
to perform but requires skill in sonographically guided procedures. In our
study, all markers were placed at the lesion site, and placement was confirmed
on follow-up mammograms showing the location of the marker with the adjacent
localizing wire. A second limitation previously reported
[9,
10] is marker migration after
placement. Migration can occur while the patient travels from the breast
imaging suite to the operating room. However, this time interval usually is
small. Reported cases of marker migration have more commonly occurred over a
period of days after the marker has been placed for percutaneous stereotactic
biopsy and has moved owing to the accordion effect and bleeding, floating
within a hematoma at the biopsy cavity, or resorption of air at the biopsy
cavity [9]. Another limitation
is cost added to the localizing procedure when a marker is used. The cost is
minimal, however, in consideration of the larger cost of inadequate excision
of a mammographically occult lesion during surgery.
Placement of a marker under sonographic guidance at needle localization is
beneficial. It aids in identifying mammographically occult lesions within
specimens and enables immediate confirmation of accurate surgical removal of
localized lesions at surgical excision. Although there was a slight increase
in the percentage of cases in which a clear inked margin was obtained, there
was no appreciable difference in the percentage of cases with close or
positive margins necessitating reexcision.
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Abstract
Introduction
