Key words
ultrasound-guided vacuum aspiration biopsy - fibroadenoma of the breast
Introduction
Fibroadenomas are the most common tumours of the female breast [1]. They originate from epithelial mesenchyme and mostly occur as solitary nodules.
These tumours are cell-rich and contain both stroma cells and epithelial components.
They manifest macroscopically as well defined, rubbery tumours with a shiny whitish,
lobulated cut surface [2]. They normally grow to around 1–2 cm and are commonly first detected on palpation.
In many instances, however, clinically asymptomatic fibroadenomas are detected as
incidental findings by modern imaging techniques in the context of breast cancer screening
[3]. Typical ultrasound findings will suggest the diagnosis, which is then confirmed
on histology using high speed punch biopsy [4].
Cyclical pain, lesions experienced by patients as aesthetically unpleasing and pronounced
carcinophobia are some of the possible indications for removal of fibroadenomas [4] and this is classically performed by excision biopsy. However, excision biopsy requires
anaesthesia. It also causes scarring of both the skin and breast tissue that in these
mostly young patients is not only cosmetically unpleasing, but can also lead to differential
diagnostic problems at future breast imaging. A minimally invasive excision technique
would therefore be beneficial [5].
The ultrasound-guided vacuum-assisted aspiration biopsy (“hand-held Mammotome” HHM)
has become a valuable tool for minimally invasive investigation of suspicious breast
lesions. In contrast to surgical excision it can be performed under local anaesthesia
and leaves neither cosmetic impairment nor problematic breast tissue scars [6], [8], [15], [23].
This study investigated the therapeutic use of ultrasound-guided vacuum-assisted biopsy
for the removal of breast fibroadenomas. In addition, complication rates and patient
satisfaction were analysed.
Materials and Methods
Over a period of 7 years 132 patients underwent an HHM procedure with the intention
of removing a fibroadenoma (fibroadenomectomy). All patients gave written consent
to the invasive procedure after being fully informed about possible risks and complications,
e.g. bleeding, infection and injury to the skin. Data acquisition was retrospective
using patient files. Follow-up breast ultrasound examinations of 132 women at an average
follow-up interval of 9 months were considered.
Breast ultrasound was performed using a Voluson 730 Expert manufactured by GE. In
each case the volume of the lesion was calculated using the ultrasound measurements
reported. The vacuum-assisted biopsies were performed using the Mammotome® HH and
EX systems (Ethicon Endosurgery, Inc. Cincinnati, OH 45242-2839 USA). Both systems
have the same following components: control module, transport cart, holster, needle
with tube system, foot switch and system software V 5.0 (product code SCMSW5). The
Mammotome® devices were operated using the modes “positioning”, “tissue biopsy” and
“empty needle”, which can be activated on the procedure monitor.
Ultrasound examination and biopsy procedure
For the biopsy procedure patients were positioned in a comfortable supine position
keeping their ipsilateral arm held up behind their head. Lesions were measured using
the ultrasound probe and lesion volume calculated. Local anaesthesia (scandicain 1 %)
was applied after careful disinfection of the area. The breast was draped with sterile
towels while the local anaesthetic took effect. A 4 mm stab incision of the skin was
then made through which the Mammotome® device needle was inserted. The needle was
placed below the focal lesion under ultrasound guidance. Negative pressure was then
used to aspirate the breast tissue into the biopsy chamber. A high-speed rotary knife
was then pushed forward to cut the aspirated tissue off the needle in a longitudinal
direction. The tissue sample could be automatically advanced to the withdrawal chamber
where it was removed using forceps. The cylindrical tissue samples measured approx.
15 mm in length and 3–5 mm in diameter depending on needle size (8 or 11 gauge). This
procedure could be repeated as often as necessary until the lesion was no longer detectable
on ultrasound. Once the biopsy was complete the skin incision was closed using a single
button suture. All patients then had a compression bandage applied for the following
24 hours.
Patient questionnaire
In order to assess the burden of the procedure for women prospectively, 30 patients
were given a questionnaire before biopsy and asked to complete it independently after
the procedure and bring it to their next follow-up appointment. Analysis was conducted
anonymously to avoid possible distorting of data.
The following questions were asked:
-
“How severe was your pain during the biopsy?” (on a scale where 0 = no pain to 10
= unbearable)
-
“How severe was your pain the day after the biopsy?” (scale from 0 = no pain to 10
= unbearable)
-
“How annoying/uncomfortable did you find the compression bandage following the biopsy?”
(not at all, a little, moderately, very, extremely)
-
“Did a haematoma develop after the biopsy?”
-
“Were there any other complications?”
-
“How satisfied are you with the biopsy method you underwent?” (on a scale of 1 = very
to 6 = not satisfied)
-
“If it were necessary, would you agree to another vacuum-assisted biopsy?”
Statistical analysis
Data analysis was performed using the following statistical tests: the Studentʼs t-test
for nondependent, normally distributed, random variables with expected value µ and
standard deviation σ; the fourfold χ2-test for distribution characteristics; the Fischer test for statistical analysis
of contingency tables with expected values less than 5.
Results
Patient characteristics
The average age of the 132 patients was 37.7 years with a standard deviation of 12.7
years ([Fig. 1]).
Fig. 1 Age distribution of patients at time of biopsy.
In the majority of cases the lesion volume was 0.51–1.5 cm3. Data on lesion size were not available for 11 biopsies ([Fig. 2]).
Fig. 2 Distribution of biopsies according to ultrasound determined lesion size.
Timing of repeat ultrasound
Follow-up ultrasound was performed at an average of 259.1 days after the procedure;
26.5 % were performed within 7 days, 9.1 % between 8 and 30 days, 35.6 % between one
month and one year and 20.5 % more than a year after the procedure. The exact timing
of repeat ultrasound could not be determined for 2.3 % of patients. In 76 % of patients
no residual tumour was demonstrated at follow-up ultrasound; in 17 % of patients residual
tumour was suspected. 7 % of cases could not be reliably assessed for residual tumour
due to either scarring or secondary haemorrhage.
Follow-up ultrasound performed within a week of biopsy showed complete fibroadenoma
excision in 74.3 % of cases. 17.1 % had residual findings and 8.6 % of cases could
not be reliably assessed due to the presence of haematoma.
Among patients who were followed up between 8 days and 1 month after the procedure
none had residual findings. Among those with follow-up between one month and one year
after the procedure 27.7 % had suspected residual tumour, 63.8 % had none and 8.5 %
could no be reliably assessed because of scar tissue. In patients with follow-up examination
after a year ultrasound showed complete fibroadenoma excision in 92.6 %. 3.7 % had
residual tumour and a further 3.7 % could not be reliably assessed.
Tumour size and residual ultrasound findings
Follow-up ultrasound findings after vacuum-assisted biopsy correlated with original
tumour size. The larger the lesion initially, the greater the risk of residual tumour
following the procedure. Complete excision was achieved in 86.7 % of lesions smaller
than 2.51 cm3 and residual tumour was significantly more likely for lesions larger than 2.51 cm3 (p < 0.05).
[Fig. 3] shows the number of procedures and number of cases with residual tumour on ultrasound
with respect to initial lesion size. For fibroadenomas smaller than 2.51 cm3 complete ultrasound-confirmed excision was achieved in 97 cases and 12 cases had
suspected residual tumour. Despite low case numbers with larger lesions there was
a trend towards an increased risk of incomplete excision for bigger tumours.
Fig. 3 Number of procedures with residual tumour on ultrasound relative to total number
of procedures according to size on initial ultrasound in cm3.
Larger tissue volumes could be obtained more quickly with 8 gauge compared to 11 gauge
needles. There was however no significant association between complete excision and
needle size.
Potential complications such as a need for hospitalisation, operative revision or
infections requiring treatment did not occur.
The procedure caused mild pain at most ([Fig. 4]). The majority of women regarded the compression bandage (applied after the procedure
until the following morning) as not very annoying. A good third of patients found
it somewhat more problematic/uncomfortable.
Fig. 4 Patient perception of pain during biopsy.
90 % of women reported developing a diffuse postinterventional haematoma (27 of 30
patients). 45 % had no hardening of the breast after vacuum-assisted biopsy; the rest
palpated a postinterventional lump between the size of a cherry and an orange.
All patients interviewed stated they would undergo this method of biopsy again if
necessary, suggesting a high level of patient satisfaction and acceptance of the procedure
([Fig. 5]).
Fig. 5 Score-based rating of the procedure.
Discussion
The vacuum-assisted aspiration biopsy is an established minimally invasive biopsy
method for the investigation of breast masses [6], [8], [13], [15]. The main advantage of this method is a reduced number of adverse effects compared
to open excision biopsy. Risks of an open surgical intervention include the potential
complications of general anaesthesia, greater blood loss and more scarring due to
a larger wound area.
Compared to other minimally invasive breast biopsy methods such as the high-speed
punch biopsy, vacuum-assisted biopsy allows the removal of greater tissue volumes,
which is advantageous when complete excision is indicated.
This study was a retrospective analysis of the therapeutic applicability of ultrasound-guided
vacuum-assisted biopsy for benign lesions of the female breast focussing specifically
on the extent to which the HHM procedure achieves complete lesion excision as assessed
by follow-up ultrasound. With ultrasound as the final measure it was shown that complete
fibroadenomectomy was achieved in 76 % of biopsy procedures.
Initial tumour size is a decisive criterion for postinterventional residual ultrasound
findings. Fibroadenomas smaller than 2.5 cm3 could be completely removed in 87.6 % of cases (p < 0.05). 37.5 % of lesions larger
than 2.5 cm3 were associated with residual findings. It is possible that lesions larger than 2.5 cm3 can not be completely removed reliably enough by vacuum-assisted biopsy. These results
are in agreement with published literature. In a current (2012) consensus recommendation
on the use and indications of ultrasound-guided vacuum-assisted aspiration biopsy
the following conclusions are drawn: Ultrasound-guided vacuum-assisted biopsy is a
suitable method for the complete excision of benign, symptomatic breast lesions and
represents an alternative to open excision [9]. Only in exceptional cases should the lesion measure over 2 cm in diameter. For
this tumour size rates of ultrasound-confirmed complete excision vary between 95 and
100 % [8], [11], [12], [14], [18], [19], [20], [22], [23]. The technique is recommended by some for removal of benign phyllodes tumours [16]. The learning curve is steep [17]. A recently published metaanalysis included studies comparing vacuum-assisted biopsy
with open biopsy for the investigation of benign tumours [7]. 15 studies were analysed including a total of 5256 patients. No differences in
tumour size, postoperative haematoma, ecchymosis, ecchymoma or residual tumour were
found between HHM and open biopsy. The HHM procedure was advantageous with respect
to size of skin incision, intraoperative blood loss, operation time, healing time,
scar size, wound infection and cosmetic breast deformity. The authors conclude that
the HHM procedure is the ideal method for removing benign breast tumours. In agreement
with our results Yom et al. found that residual benign tumour was more seldom the
later follow-up ultrasound was performed: when follow-up was within 2 years of the
procedure residual tumour was found in 10 % of cases and scar tissue in 36 %. Beyond
2 years these figures were only 6.5 and 15.8 % respectively [23]. The early follow-up in our study collective possibly explains the relatively high
rate of suspected residual tumour.
Ultrasound-guided vacuum-assisted biopsy is almost painless.
Vacuum-assisted biopsy is a safe method of biopsy associated with few complications
and only mild pain during and after the procedure. The low degree of associated pain
has been confirmed by other studies. Despite its thicker needle the procedure does
not cause more discomfort than high-speed punch biopsy [21]. Haematoma formation is the most common complication. 27 out of 30 patients reported
haematoma development though the majority were not of therapeutic consequence [7], [10], [13], [14]. In our survey all patients stated they would undergo the biopsy again if necessary.
High patient satisfaction with the procedure has also been reported by others [22].
Thus the vacuum-assisted breast biopsy is an appropriate, effective and accepted method
for the excision of benign breast lesions.
