2012 EDUCATIONAL BOOK - American Society of Clinical Oncology

mographically detected recurrence, or in asymptomatic patients.
They also demonstrated an absolute reduction in
mortality of 17% to 28% in all patients with breast cancers
found early.
A recent review in the United Kingdom for the Health
Technology Assessment by Robertson and colleagues 17 also
demonstrated that for screening for local recurrence, surveillance
mammography sensitivity ranged from 64% to 67%
and specificity ranged from 85% to 97%. They also found
that for MRI, sensitivity ranged from 86% to 100% and
specificity was 93%. They concluded that mammography is
associated with a high sensitivity and specificity but that
MRI is the most accurate test for detecting local recurrence.
Developing Role of MRI Post-BCT Surveillance
MRI is emerging as a valuable tool in the treatment of
patients with a diagnosis of breast cancer. Conventional
imaging techniques of mammography and US can be difficult
to interpret as a result of post-therapeutic changes, and
some centers are including breast MRI in the surveillance of
women who are post-BCT, as surveillance MRI in this
population has been shown to detect malignancy in 12%. 18
In the Robertson review, 17 MRI was found to be the most
accurate test for detecting ipsilateral tumor recurrence and
contralateral breast cancer in women previously treated for
primary breast cancer. MRI in combination with mammography,
US, and clinical examination has been reported to
have a sensitivity as high as 100% and specificity of 89% for
detecting contralateral breast cancer in patients who have
undergone BCT. 19 MRI has been shown to be extremely useful
in differentiating scar tissue from tumor recurrence, particularly
in showing that nonenhancing areas have a high
negative predictive value for malignancy (88% to 96%). 20,21
The use of MRI in the monitoring of the post-BCT breast
is variable and often at the discretion of the ordering
physician or surgeon. The American College of Radiology
practice guidelines state that breast MRI may be useful for
women with a prior history of breast cancer and suspicion of
recurrence when clinical, mammographic, and/or sonographic
findings are inconclusive. 22 Although women with
a previous diagnosis of breast cancer are at increased risk of
a second diagnosis, an American Cancer Society panel concluded
that the increased risk due to a personal history of
breast cancer alone does not justify a recommendation for
overall screening in women post-BCT at the present time. 23
Neither National Comprehensive Cancer Network nor
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KEY POINTS
● Mammographic surveillance has a high sensitivity
and specificity for recurrent malignancy.
● Magnetic resonance imaging is the most sensitive
and accurate tool for evaluation of the postoperative
breast.
● Physical examination has an important role in surveillance.
● Robust conclusions cannot be made because of the
limited evidence base.
● Further research comparing surveillance mammography
and newer diagnostic tests is required.
ASCO guidelines consider MRI for surveillance. Changes
occurring after BCT on MRI are similar to those described
on mammography and include architectural distortion,
edema, skin thickening, and occasionally a seroma. These
findings are typical and may stabilize or continue to decrease
over time. Enhancement at the lumpectomy site can
be an expected finding depending on the time interval from
BCT. A minimal or small focal area of thin linear enhancement
can be seen for up to 18 months, and in some cases
even longer. 24,25 On follow-up imaging, enhancement should
demonstrate stability or decrease over time. Fat necrosis is
commonly present in the post-BCT breast and can be a
challenging pitfall, often leading to biopsy. Enhancement is
variable in appearance and kinetic patterns. Biopsy may be
avoided if the MRI signal is similar to that of adjacent fat on
unenhanced images and the lesion shows no internal enhancement.
For this reason, nonfat-saturated T1-weighted
sequences should be included on all breast MRI patients.
Mass-like enhancement at the lumpectomy site is always
suspicious and requires biopsy. Similarly, clumped, new, or
increasing areas of nonmass-like enhancement (not associated
with fat necrosis) should be considered suspicious. 26
Much of the utilization of MRI is physician- or surgeondependent.
Many centers stagger MRI and mammograms at
6-month intervals. The reasoning behind this is that the
breast is surveyed in a different modality every 6 months. At
our institution, we prefer that MRI be performed 1 year
following surgery, so that it coincides with the bilateral
mammographic exam. This clarifies indeterminate findings
in the contralateral breast and allows normal postsurgical/
radiation therapy enhancement to decrease. Either approach
is acceptable, as there are no specific data-driven
guidelines or a consensus on recommendations for MRI
surveillance intervals in this population. Despite breast
cancer survivors having a high risk of second cancer,
Punglia and Hassett 27 recommend against routine MRI,
suggesting selective use by lifetime risk estimates.
Breast Conservation Surveillance
All agree that surveillance of patients who are post-BCT is
necessary. However, there is a lack of consensus on how
frequently and for how long we should provide routine
surveillance after treatment. Subsequently, there are several
ways that surveillance can take place and may vary
from institution to institution (Table 1). The majority of
centers surveyed for this article have a common initial
2-year pathway, changing to annual follow-up at year 3.
Benign Findings Mimicking Malignancy
FLOWERS, MOONEY, AND DRUKTEINIS
There are many benign findings that can mimic malignancy
in the postsurgical breast, but essentially they may be
broken down into two categories: a) developing microcalcification,
and b) variants of fat necrosis. The aggressive variant
of fat necrosis can produce a very hard, spiculate scar.
The matrix may also calcify without the characteristic
dystrophic calcification that is normally associated with it.
This variant often produces a fine, lace-like, rapidly developing
calcification, prompting biopsy.
Calcifications may develop in a patient who has been
treated for ductal carcinoma in situ (DCIS), especially if
there was noncalcified disease followed by radiation therapy.
There may be an increase in necrosis due to apoptosis of