NEW ORLEANSThe diagnosis of breast cancer is becoming
less invasive and far more accurate, said Steve H. Parker, MD,
director of the Sally Jobe Breast Centre, Denver. Dr. Parker
delivered the plenary lecture at the American Society of Breast
Disease annual meeting, cosponsored by the Ochsner Medical Foundation.
Advances in Ultrasound
New ultrasonography technology has had a dramatic impact on breast
imaging in the last 5 years. In fact, you should be wary of any
radiologist using equipment that is older than this, Dr. Parker
said, noting that such technology is already largely out of date.
New breast-specific software and very-high-frequency,
broad-band-width transducers have allowed for excellent resolution of
very small structures within the breast and the detection of
subcentimeter cancers. This technology can differentiate between
solid lesions that should be biopsied and those that can be followed.
The dictum biopsy all thats solid is an
outdated concept, he said, but you have to have the best
equipment and experienced radiologists.
Microcalcifications that require biopsy should generally be
approached with stereotactic mammographic guidance. Most stereotactic
units now have digital imaging that provides superior contrast
resolution and near-instantaneous image display, compared with
film-screen imaging. These units are ideal for specimen
radiography as well as ductography and the workup of
microcalcifications, he commented.
Several manufacturers now offer full-field digital mammography that
promises to provide superior contrast resolution, increased
throughput, and reduced radiation exposure, compared with standard
film screening mammography. However, these devices are not yet FDA
approved and are still quite expensive, Dr. Parker said.
Breast MRI (dynamic or high-resolution), while also expensive, has
been approved by the FDA. We have found it to be an
exceptionally helpful tool in treatment planning, Dr. Parker
said. Both types of breast MRI utilize gadolinium contrast injection.
Dynamic breast MRI images the breast in the first 90 seconds after
injection, which gives poor spatial resolution and sensitivity but
offers improved specificity, compared with high-resolution breast MRI.
High-resolution RODEO (ROtating Delivery of Excitation Off-resonance]
MRI offers very high sensitivity with spectacular spatial resolution
but poorer specificity. With RODEO, a follow-up ultrasound is
recommended to determine the need for biopsy, he noted.
RODEO MRI is most useful in the preoperative assessment of a
patient who has a dense mammogram and a biopsy-proven infiltrating
lobular carcinoma in situ (LCIS) (see
Figure 1), ductal carcinoma in situ (DCIS), or infiltrating duct
carcinoma with DCIS, he said. In these instances, the
true extent of disease is much better appreciated than with standard
mammographic images, and the surgery can be appropriately tailored.
Dr. Parker stressed that we are not using breast MRI to
determine benign vs malignant disease, but to look at cancer and see
how best to treat it. The 3D image shows you the areas of
enhancement. We have been inundated by requests for breast MRI from
surgeons and oncolgists. In fact, our outpatient scanner is becoming
almost totally a breast MR scanner. Thats how many we are doing.
In concert with the improvements in imaging, there have been marked
improvements in tissue acquisition as well. The Mammotome
(directional vacuum-assisted biopsy using a thin rotating blade),
which was introduced in 1995 and which Dr. Parker helped develop,
allows a greater amount of tissue to be harvested in a much shorter
time (see Figure 2 ). In addition,
the tissue is obtained contiguously, leaving no region of the
biopsied area unsampled.
The Mammotome, which is used with ultrasound guidance, has solved the
problem of underestimation of disease by standard automated core
biopsy, he said. There is nothing left unsampled, he
noted. Its an unequivocal biopsy.
Dr. Parker uses an 11-gauge Mammotome needle for stereotactic biopsy,
primarily for calcifications but also for small breast masses, and a
14-gauge needle for core biopsy of lesions greater than 1.5 cm.
The success of these new instruments in removing entire malignancies
has opened the possibility of actually using image-guided diagnostic
biopsy in place of standard surgical lumpectomy, he pointed out.
However, thus far it has been difficult to predict the margin status
with these devices.
Other investigators are pursuing the possibility of in situ ablation
with stereotactic or MRI-guided laser therapy and ultrasound-guided
cryotherapy. It is likely that some form of percutaneous lesion
removal, perhaps combined with sentinel node biopsy or in situ
ablation, may be forthcoming, he said.
I am convinced that there will come a time when the removal of
small cancers will require only a small hole over the lesion and one
over the axilla. You wont be able to tell the surgeon has been
there, Dr. Parker predicted.