CHICAGO — A novel procedure that combines mammographically guided hook-wire localization followed by ultrasound-guided sampling provides a minimally invasive alternative to stereotactic biopsy of breast calcifications.
The combination procedure was used in 57 groups of microcalcifications in 48 women, aged 41–79 years, who failed or were unable to have a stereotactic biopsy. The procedures were performed between January 2001 and September 2008 at Metro Health Medical Center, an inner-city county hospital in Cleveland.
In all, 52 of the 57 groups of microcalcifications were successfully sampled, resulting in a 9% failure rate, Dr. Jill J. Schieda and her colleagues reported at the annual meeting of the Radiological Society of North America. The procedure was considered a success if the targeted calcifications were identified on specimen radiography and in the specimen by pathology. There were no postprocedural adverse events.
Two of the five failures were due to the inability to place the hook wire sufficiently close to the targeted calcifications, and one was due to excessive patient motion. In one patient, the calcification was too close to the skin, and in another patient the procedure was technically successful but no microcalcifications were seen on radiography. Three of these five patients successfully underwent the procedure within 2–6 months of the first failed attempt.
“Although the combination procedure is time consuming, the patient may be saved from unnecessary surgery, which is definitely an advantage,” said Dr. Schieda, a radiology resident at the hospital.
Approximately 3% of stereotactic biopsies are unsuccessful, typically because the calcification is not visible on mammography; excessive patient motion or the inability of the patient to get on the stereotactic table may also be problems.
In such cases, the options are limited to open surgical biopsy or imaging follow-up, she said.
During the combined procedure, mammographic guidance is used to place the hook wire just anterior to the calcifications of interest, preferably using a craniocaudal approach. One wire is usually used, but multiple wires can be deployed if additional groups of calcifications are being biopsied or if placement of the primary wire is unsatisfactory because of patient motion, Dr. Schieda said in an interview.
The depth of the wire is adjusted, and the relationship between sonographically visible markers on the wire and the calcifications is documented with a mammogram. If the wire is placed properly, the calcification should be located at the junction of the first set of markers, which look like beads on the wire, she said.
With ultrasound guidance, a large-core vacuum-assisted device is placed just deep to the wire, adjacent to the known location of the calcifications. Sampling is done with the open cutting aperture rotated toward the calcifications, with care taken not to engage the wire within the cutting aperture.
Dr. Schieda acknowledged that the procedure requires significant patient cooperation and performer experience. The same breast-imaging radiologist performed all the procedures in this investigation; although the procedure is novel, the radiologist's 30 years of professional experience may have shortened the learning curve.
Limitations of the study include the small population, lack of a gold standard for comparison, and lower-than-usual resolution of the hospital's stereotactic unit, which may have influenced the need for the alternative procedure.
The investigators reported no conflicts of interest or funding sources for the study.
In this medial-lateral view of the breast, the calcifications, indicated by dashes, are posterior to the wire and near the junction of the first set of tight and loose beads. The arrow is anterior to the wire and is directed toward the calcifications. Courtesy Dr. Jill J. Schieda/Dr. Mark Rzeszotarski