|
OTHER PUBLICATIONS BY DR. HOLLINGSWORTH
(and, since
2000, the Mercy Women's Center team):
Featured Article
A Surgeon’s View of Breast MRI
by Alan B.
Hollingsworth, M.D.
In 1990, I saw my first ‘spinning hologram’ of RODEO
MRI in a presentation by Dr. Steven Harms at a breast conference in
Dallas. On the “inside” of this 3-D breast image was a cancer NOT SEEN
on mammography. This led me to ask the question: “Why don’t all cancers
show up on mammography?” Today, we know the answer, but at the time,
this information was not generally appreciated, and a literature review
revealed only three papers on the subject, implicating one special type
of cancer that was particularly elusive (invasive lobular cancer).
With my strong interest in breast pathology, I
reviewed the experience at my institution that resulted in a paper
entitled, "The Histologic Basis of False Negative Mammograms" that was
published in the American Journal of Surgery. In that paper, where I
served as the quasi-pathologist doing all the photography myself, I
described tumor growth patterns, even with the more common invasive ductal carcinoma, that would be very unlikely to be picked up by
mammography (depending on the density of the normal breast tissue
touching the tumor). The conclusion of that paper states that
mammography is a strictly “anatomic” picture of breast tissue, and…given
the growth patterns of certain tumors, an anatomic approach alone
(mammography) will NEVER be perfected…that a physiologic parameter MUST
be added to the anatomic picture to make cancer stand out.” When the
Golden Anniversary Issue of the American Journal of Surgery was
published years later, they selected this article as one of the most
outstanding contributions among their Oncology publications for the past
50 years.
Mammography has the distinct advantage of revealing
tiny flecks of calcium that can lead to the earliest forms of breast
cancer (calcium doesn’t show up well on MRI). These calcium flecks can
show up nicely even in dense breast tissue. But there’s one problem here
– most breast cancers become invasive WITHOUT developing mammographic
calcium. And if there’s no calcium, and if the growth pattern of the
tumor blends in with the breast tissue, then a good portion of the
breast can be involved by cancer, yet the patient can still have a
normal mammogram and normal exam. And this is the paradox of mammography
– it is the modality that finds the earliest form of breast cancer,
while at the same time can miss large cancers!
When “failure to diagnose breast cancer” moved into
the Number One Slot under reasons for malpractice litigation, it was
found that in 80% of cases, the MAMMOGRAMS ARE NEGATIVE. And typically,
this occurs in younger women where the breast tissue is denser, and more
capable of hiding cancer.
I believe there has been a delay in recognizing the
magnitude of this problem because the “breast community” for many years
became infatuated with their own strides in discovering the earliest
form of breast cancer – DCIS. Prior to mammography, this was a rare
find, less than 5% of cases. Now, if your cancer is diagnosed by
mammography, then odds are 25-40% that it will be DCIS. That’s great,
but what about the remainder? Many of the women whose cancers do not
appear on X-ray show up in the surgeon’s office with a palpable lump,
NOT at the mammography centers where their mammograms were “normal.”
Therefore, it’s not so unusual for a surgeon to be interested in the MRI
revolution. For you see, MRI adds the “physiologic parameter” I
mentioned above – by injecting the contrast agent gadolinium, cancer is
“enhanced.” Thus, the ‘diffuse’ cancers (lobular and some ductals) show
up as a result of the contrast, especially when hundreds of images are
taken with MRI.
MRI has been available for the rest of the body for
over 20 years. Even with contrast, it was delayed in its introduction
for routine clinical use for several reasons: 1) there was no “normal”
breast pattern to serve as a baseline, i.e., there’s an infinite number
of “normals.” Thus, it is actually far easier to learn brain anatomy on MRI than
breast anatomy. 2) there were competing technologies related to
timing of contrast vs. morphology of contrast; and while these issues
are not completely settled, great advances have been made and
technologies have been merging. 3) until recently, there was no way to
perform a reliable MR-guided biopsy. The needle would appear on the MR
image, but it wouldn’t be exactly where it needed to be because of a
distortion artifact. With this problem now behind us, MRI is ready for
expanded clinical use.
Here’s my short-term vision: The work-up for breast
cancer will be a needle biopsy, then the next step is a MRI, then the
patient will meet the surgeon who will have an accurate map of the
problem. Published studies indicate a major change in surgical plans in
10-20% of patients who undergo pre-op MRI. If 200,000 women undergo
surgery each year for breast cancer, is it really possible that we’re
doing the wrong surgery on 20-40,000 women each year?! Yes, it is. Even
a fraction of that number is unacceptable. It’s time to pull our heads
out of the sand, and operate on what’s really in the breast, not what a
grossly inaccurate measure of tumor involvement (mammography) indicates.
And here’s my long-term vision: With MRI of the
breast having 95-100% sensitivity for the detection of breast cancer, we
need a pre-screen with a blood test ... desperately. It will come.
Someone will do it, or perhaps the combination of several tests will
detect early breast cancer. When it happens, this is what you’ll see for
screening: Mammography AND the blood test. If the blood test is positive
for cancer, but mammograms negative, patients will have screening
ultrasound and MRI performed. HOWEVER, if a blood test is found with
near-100% sensitivity, Screening Mammography will become a thing of the
past. Only those women with positive blood testing will undergo
diagnostic mammography, ultrasound, and MRI to locate the problem
already identified by the blood test.
It was 1990 when I latched onto breast MRI as our
answer to so many problems. While false-positives and high cost will
still be with us, improvements will occur. Meanwhile, the rate of
“missed cancers” will start to fall. When the screening blood test is
found, the rate of “missed cancers” will drop precipitously for then we
can better identify asymptomatic women who need this “new” modality.
|
