2012 EDUCATIONAL BOOK - American Society of Clinical Oncology

Fig. 1. A clip from the newspaper regarding 3-day as a new
technology for screening.
screening. There are multiple ongoing studies to better
define its strengths and weaknesses and to determine its
ideal role.
Contrast-Enhanced Mammography
Contrast-enhanced breast MRI functions by both defining
anatomic abnormalities and evaluating physiologic changes
related to the development of neovascularity, which are
visualized by their rapid contrast enhancement in cancers.
MRI has proven to be exquisitely sensitive for the detection
of breast cancer, with a sensitivity range from 79% to
98%. 9,10 A meta-analysis has shown that MRI also detects
mammographically occult multicentric or multifocal disease
in approximately 16% of patients with known breast cancer.
9
Although breast MRI is extremely sensitive, specificity is
more limited, leading to additional workups and benign
biopsies. Additionally, it is expensive, and good quality
66
KEY POINTS
● Mammography is the only breast imaging exam
known to reduce breast cancer mortality, but sensitivity
is limited particularly in high-risk women with
dense breast tissue.
● The digital mammography platform has allowed for
developments such as tomosynthesis and contrastenhanced
mammography, which have the potential to
improve sensitivity.
● Ultrasound detects additional cancers but at the cost
of many benign biopsies. Potential advances in ultrasound
technology include automated whole-breast
scanning, elastography, and microbubbles.
● Breast MRI remains the most sensitive examination
for the detection of early-stage breast cancer in a
high-risk screening population.
● Radionuclide breast imaging is able to detect breast
cancers independent of breast density, but its high
extramammary radiation dose precludes use in
screening.
MAXINE JOCHELSON
breast MRI is not universally available. Patients with pacemakers,
certain aneurysm clips or other metallic hardware,
and severe claustrophobia are unable to undergo MRI.
Contrast-enhanced mammography has been developed to
potentially duplicate the capacity of MRI to detect and stage
breast cancer with the use of both anatomy and physiology.
It has been investigated both as an adjunct to mammography
and an alternative to MRI. 11,12 It uses the same iodinated
contrast used for CT in the same doses.
Hardware and software adaptations to digital mammography
units that automate a dual energy technique have
been developed. This technology, known as Contrast-
Enhanced Spectral Mammography (CESM), received FDA
approval in 2011. It provides two images in each view: a
low-energy image, which is below the K-edge of iodine
(33.2keV), and a high-energy image, just above. The two
images are combined and processed so that the background
breast tissue is essentially subtracted out, maximizing
the ability to see areas of enhancement (Fig. 2). There is a
20% additional radiation dose, which is the equivalent of
one extra mammographic view. The examination takes approximately
10 minutes to perform and is only slightly
longer than a mammogram to read. It is well tolerated by
patients.
Dromain and colleagues recently reported a comparison
of contrast-enhanced digital mammography (CEDM) plus
mammography with mammography alone and mammography
plus ultrasound in 142 lesions in 120 patients. Sensitivity
for CEDM plus mammography was 93% compared with
78% (p � 0.001) for mammography alone. Specificity was
unchanged. There was improvement in sensitivity and specificity
between CEDM plus mammography and ultrasound
plus mammography, but it was not significantly better.
Additionally, all 23 multifocal lesions were detected. 13
Jochelson reported early results of a comparison of CEDM
with breast MRI in 26 patients with known breast cancer.
The two examinations each detected 25 of 26 index tumors
compared with the 22 detected by mammography alone.
MRI was more sensitive than CEDM for the detection of
additional lesions (7 vs. 5), but there were no false-positive
CEDM examinations and seven false-positive MRIs. 14 Results
on additional patients will be reported later this year.
The early data for CESM are promising but require
confirmation. Screening studies need to be performed. If
larger studies confirm early results, CESM could become
available as a possible “poor woman’s” MRI. Larger multiinstitutional
trials are ongoing.
Ultrasound
Targeted breast ultrasound is of value in further defining
mammographic and MRI abnormalities as well as evaluating
palpable lesions. Ultrasound-guided core biopsies are
an effective means of obtaining histologic diagnosis. Ultrasound
is inexpensive, utilizes no radiation, and is widely
available.
The use of ultrasound for screening is more problematic.
Multiple studies, including a large ACRIN trial evaluating
the utility of ultrasound screening in high-risk patients,
have shown that ultrasound will detect additional cancers
in three to four of 1,000 patients (as compared with MRI,
which detects additional cancers in four to five of 100
patients). 15,16 In doing so, a large number of additional
lesions are detected leading to short-interval follow-ups or