Breast cancer affects approximately one out
of every eight women in her lifetime and is the second leading cause of cancer
death among American women 1. Mammography is the primary screening
and diagnostic tool for breast cancer. Especially early signs of breast cancer
such as microcalcifications, architecture distortions, and asymmetries may only
be found on the mammography. Thus, screening with mammography allows detecting
breast cancer in an early stage and reduces the death rate2. But, it
still has decreased sensitivity and high false-positive recalls rate especially
in women with dense breasts. Dense breast tissue can mask breast cancer which
called ‘masking effect’ and cause false-negative results3,4.
Suspicious lesions for breast cancer are often sampled through mammographic
guidance, which is known as prone stereotactic vacuum assisted biopsy (SVAB).
While SVAB is a reliable and safe method for breast tissue sampling and has
widely used in almost all imaging practice, it also has some drawbacks,
including demanding procedure planning and lack of depth information of the
targets5,6.

A newly emerging technology, Digital breast
tomosynthesis (DBT) or 3D mammography can reduce the masking effect of the
breast tissue on mammography by creating multiple 2D imaging slices of the
breast. Hence, it has been proven to have higher breast cancer detection rate
compared with 2D mammography7,8. Recent researches also demonstrates
that DBT improves the detection of microcalcifications as well as low contrast
lesions such as uncalcified masses or architectural distortions9.
Moreover, it has lower false-positive rates which helps to avoid unnecessary
recalls and further evaluation10,11. Therefore, DBT has already been
suggested and used as an alternative screening methods to 2D mammography for
breast cancer12.

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DBT
guided vacuum assisted biopsy (DVAB) is a new and accurate method that allows
sampling the lesions that found on both 2D and 3D mammography. It can also
provide the depth of the lesions and biopsy needles along the z-axis thus
making the procedure planning more straightforward and faster13-16.

The
objective of our study is to describe our preliminary experience with DBT
guided vacuum assisted biopsy in order to evaluate its the clinical performance
and compare it with that of the conventional prone stereotactic biopsy.

 

1.     
MATERIALS
and METHODS

This
retrospective study was approved by the authors’ institutional review board.
Because of its retrospective design, no informed consent was obtained from
patients to participate in the study.

Patients
were selected from a search of the Radiology Information System as well as the
patient’s medical records. No advertising or face-to-face interview with
subjects occurred.

2.1.Study
Group

From
1 May 2013 through 30 April 2017, all women who had underwent either the DVAB
and SVAB procedures were included in the study. Patients were selected without
regard to their ethnicity or the language they spoke.

Between
1 May 2013 and 30 April 2015, in a two years period, all lesions were biopsied
by using SVAB. After installation of DBT-guided biopsy system (May 2015),
during a month transition period, both systems (SVAB and DVAB) were used for
biopsy procedures. Since June 2015, all biopsy procedures were performed by
using only DVAB.

2.2.Biopsy
Procedures

Biopsies
were performed by a pool of experienced breast radiologists who worked on the
department of breast radiology.

SVAB was performed
with the patient in a prone position with a dedicated system (Lorad Multicare Platinum;
Hologic) by using a standard technique described previously17.
After positioning the patient,
the breast was compressed by a dedicated compression plate with a 5×5 cm biopsy
window. Then, the lesion was identified and carefully positioned in the center
of the biopsy window which was controlled by a scout mammogram. Also, two
additional projections at +15 and -15 degrees were performed to calculate the coordinates of the target lesion for
needle insertion.

DVAB was performed with using a full-field digital
mammography system equipped with a three-dimensional tomosynthesis platform (Selenia Dimensions 3D; Hologic)
and with a dedicated guidance system
add-on. During the biopsy procedures, the full detector field was used. This
provides the biopsy window in different sizes due to the type of the paddle
that was used for compression. The DBT images maintained all of the biopsy
coordinates including the depth of the target lesion for needle insertion. All
the patients were positioned in a sitting position on a dedicated armchair.

The
sampling procedure and needle sizes were not different between SVAB and DVAB procedures. During performance of
both systems, a couple of images were obtained to localize the target lesion,
to verify the pre-fire needle position, to document the needle in post-fire
position. Pre- and postbiopsy patient care
was standardized and followed written institutional guidelines.

If
the biopsy procedure was aborted for any reason in both systems, the reason was
reported.

2.3.Data
Analysis

The
target lesions were categorized as high-contrast lesions and low-contrast
lesions according to the mammographic findings. 
Microcalcifications with or without accompanying mass/architectural
distortions were classified as high-contrast lesions whereas architectural
distortions, asymmetries, and masses without calcifications were classified as
low-contrast lesions.

The
final pathology results were categorized into three groups; group 1: benign
changes, group 2: high risk changes, and group 3: malignant lesions with
subtypes such as ductal carcinoma in situ (DCIS) and invasive breast cancer.

2.4.Statistical
Analysis

All
statistical analysis were performed with SPSS software version 20.0 (IBM,
Chicago, IL). The x2 tests and Student t tests were used to compare
patient demographics, the rate of aborted procedures, the causes of abortions,
as well as the radiologic and pathologic properties of lesions for SVAB versus
DVAB. The significance level was accepted as p